[Patch Darwin 2/2] fix PPC64 ABI

[IainS]

On 26 Jul 2010, at 14:33, Nathan Froyd wrote:

> On Sat, Jul 24, 2010 at 12:43:52PM +0100, IainS wrote:
>> On 24 Jul 2010, at 11:13, Nathan Froyd wrote:
>>> Could we avoid introducing more #if TARGET_MACHO where it's not
>>> necessary?  It should be sufficient to say something like:
>>>
>>> if (TARGET_MACHO
>>>     && rs6000_darwin_abi
>>>     && integer_zerop (TYPE_SIZE (type)))
>>>   ...
>>>
>>> and the compiler will DTRT and fold out that code for non-Darwin
>>> targets.  (This comment applies equally to your other darwin64  
>>> patch.)
>>
>> sure, if that's the preference, no problem.
>> I guess I was thinking that it would be better to eliminate the  
>> code  at
>> pre-processing
>
> It does slightly speed things up (I doubt that you'd notice the  
> speedup,
> really).  The rationale for using:
>
>  if (TARGET_MACHO)
>
> versus
>
>  #if TARGET_MACHO
>
> is that with the former, the compiler will validate that the code
> syntax-checks and type-checks even when compiling for non-Darwin
> targets.  This extra checking makes it slightly harder to  
> inadvertently
> break things.

OK. I'll do a second pass through (after sorting out part #3 of the  
ABI fixes).

Apropos extending this to its logical conclusion:

I suspect that the only viable 'end-game' at present is to macro-ize  
the machopic* calls,
exposing the whole of the machopic workings would probably carry too  
much weight.

(that comment would apply equally to i386.c, which also uses that  
machopic common code).

Iain