GDC review process.

[Manu]

On 19 June 2012 23:03, Walter Bright <newshound2 at digitalmars.com> wrote:

> On 6/19/2012 11:57 AM, Iain Buclaw wrote:
>
>> To quote from one of the i386 backend maintainers:
>> ---
>> "Does D *really* require a new calling convention?
>>
>
> No, but the idea was to allow D to innovate on calling conventions without
> disturbing code that needed to interface with C.
>

Properly implemented multiple-return-values being the killer app here!
Using ALL the argument registers for returning multiple values aswell ;)


 Also does it *really* require naked support?
>> I think naked support is a bad idea
>> and people who require naked support should be writing an assembly
>> function wrapper."
>> ---
>>
>
> Naked support allows people to write max efficient assembler without
> needing to exit the language and use the (often miserable) standalone
> assembler.
>

I find a thorough suite of architecture intrinsics are usually the fastest
and cleanest way to the best possible code, although 'naked' may be handy
in this circumstance too...
If a function is written from intrinsics, then it can inline and better
adapt to the calling context. It's very common that you use asm to write
super-efficient micro-function (memory copying/compression, linear algebra,
matrix routines, DSPs, etc), which are classic candidates for being inlined.
So I maintain, naked is useful, but asm is not (assuming you have a high
level way to address registers like the stack pointer directly).


Thinking more about the implications of removing the inline asm, what would
REALLY roxors, would be a keyword to insist a variable is represented by a
register, and by extension, to associate it with a specific register:
  register int x;             // compiler assigns an unused register,
promises it will remain resident, error if it can't maintain promise.
  register int x : rsp;    // x aliases RSP; can now produce a function
pre/postable in high level code.
Repeat for the argument registers -> readable, high-level custom calling
conventions!

This would almost entirely eliminate the usefulness of an inline assembler.
Better yet, this could use the 'new' attribute syntax, which most agree
will support arguments:
@register(rsp) int x;
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