DMD compiler switch to set default extern() linkage?

[Iain Buclaw]

On 5 April 2012 11:28, Alex Rønne Petersen <xtzgzorex at gmail.com> wrote:
> On 05-04-2012 12:16, Dmitry Olshansky wrote:
>>
>> On 05.04.2012 13:49, Alex Rønne Petersen wrote:
>>>
>>> Hi,
>>>
>>> It is no secret that DMD is the only compiler in existence that follows
>>> the "D" calling convention (and even then, only on some platforms,
>>> seemingly?).
>>
>>
>> IMHO It's the only sane convention I've seen. C's default of caller-side
>> cleanup adds nothing but a mess for years to clean up. And code size
>> bloat for no good reason. I think it was just a "cool trick" to make
>> printf work, bleh. And extern(D) still allows that.
>
>
> Right. I won't deny that the "D" calling convention is good, but supporting
> it is not practical.
>
>
>>
>> Both GDC and LDC use the C calling convention of the
>>>
>>> platform by default (and don't even have options to use the "D" calling
>>> convention because their back ends don't support it at all).
>>>
>>> I'm writing a virtual machine. As far as I am concerned, the "D" calling
>>> convention adds nothing but complexity to the configuration support
>>> matrix. The calling convention situation across platforms is already
>>> utterly insane enough as it is. I would not have a problem with
>>> supporting the "D" calling convention if all compilers followed it. But
>>> they don't. And it is only specified for x86. Even in an ideal world,
>>> the "D" calling convention won't exist everywhere because it isn't
>>> intended to.
>>>
>>> So yes, we could just say "but eventually, those compilers should
>>> support it!".
>>
>>
>> Yup, let's stop being kids and copying whatever big ones are doing.
>> Standards sort of happen like this: people just start doing things
>> differently, then others like it and follow suit and then it's all
>> written on a bunch (virtual) paper with ISO number somewhere.
>
>
> Good luck convincing the GCC guys to merge your D ABI patch. ;)
>

They were equally mortified when I mentioned 'naked' functions. :~)


Point 2: If I were to be picky, the spec says that the extern (C) and
extern (D) calling convention matches the C calling convention used by
the supported C compiler on the host system. Except that the extern
(D) calling convention for Windows x86 is described here.

So as far as I am concerned GDC follows the specification of the D
language to the letter, except maybe for Windows x86 - but I don't
think MinGW counts as the same platform - so it is all still
debatable. ;)


-- 
Iain Buclaw

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