GDC review process.

[Iain Buclaw]

On 20 June 2012 17:23, deadalnix <deadalnix at gmail.com> wrote:
> Le 20/06/2012 18:18, Iain Buclaw a écrit :
>>
>> On 20 June 2012 17:00, Brad Anderson<eco at gnuk.net>  wrote:
>>>
>>> On Tue, Jun 19, 2012 at 12:19 PM, Iain Buclaw<ibuclaw at ubuntu.com>  wrote:
>>>
>>>>
>>>> Hi,
>>>>
>>>> Had round one of the code review process, so I'm going to post the main
>>>> issues here that most affect D users / the platforms they want to run on
>>>> /
>>>> the compiler version they want to use.
>>>>
>>>>
>>>>
>>>> 1) D Inline Asm and naked function support is raising far too many alarm
>>>> bells. So would just be easier to remove it and avoid all the other
>>>> comments
>>>> on why we need middle-end and backend headers in gdc.
>>>>
>>>>
>>>> 2) Code with #if V1 and V2 raised another bell with the request to
>>>> remove
>>>> all code that relies on internal macros with proper if() conditions. If
>>>> something is always going to be turned off, remove it.
>>>>
>>>> So, we shall also be saying bye bye D1 in GDC.  We'll miss you!
>>>>
>>>>
>>>> 3) For anyone who has submitted patches for Mingw and Apple - sorry, but
>>>> I'm going to have to yank out or alter certain bits.  Apple GCC is
>>>> irrelevant now, and some Mingw checks look for if(target) when it should
>>>> really be checking if(host) and vice versa!
>>>>
>>>>
>>>> Most discussion I would imagine be on the decision to remove D inline
>>>> assembler support from gdc.  So, nay sayers, do your worst, but
>>>> unfortunately there is a +1 here for removal.
>>>>
>>>>
>>>> Regards
>>>> Iain
>>>
>>>
>>>
>>> I'm very much outside of my area of understanding but would it be
>>> possible
>>> to use CTFE+mixin to generate GCC asm from DMD style asm allowing people
>>> to
>>> still use a single version of the asm for both DMD and GDC?
>>>
>>> Regards,
>>> Brad Anderson
>>
>>
>> Hmm... doable, yes, but it would require a similarly complex construct
>> as the implementation in the compiler.  GCC Assembler is much more
>> expressive than D Inline Assembler, and requires for you to describe
>> everything a given asm command is doing, inputs, outputs, clobbers,
>> and labels that we may jump to (if any).   The only thing I worry is
>> that CTFE is not powerful enough process a long set of instructions at
>> a fast enough rate to make it benefitial.
>>
>
> Can't gdc frontend process asm to gcc's asm and go from that ?

It's what we did, but there's a lot of information that we require
about, eg: the function frame pointer, that is not available to the
frontend when trying to re-create just exactly what the assembly code
is requiring us to do.

-- 
Iain Buclaw

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