Any chance of getting this patch in the tree? If it needs more time
to bake, that's fine, but if the-sbcl-powers-that-be are against the
idea, I'd like to understand why.
On Oct 3, 2005, at 10:38 AM, James Y Knight wrote:
> On Oct 3, 2005, at 12:25 PM, Cyrus Harmon wrote:
>>> Since compiler writers don't use completely random alignment rules,
>>> it might be better to have one :maximum-alignment key for the whole
>> Yes, this might be a better approach for this particular problem.
>> This route seemed more expedient, but I'm open to suggestions on
>> how to handle this as you describe.
> In GCC, at least, you can specify the minimum alignment, both on
> the structure itself, and on each data member individually. Setting
> the alignment on the structure affects its placement in other
> structures (but doesn't affect the data members inside it), and
> setting the alignment of its data members affects that member (and
> by implication, the default alignment of the struct as a whole).
> The specified alignment doesn't override the normal rules for
> alignment, and thus you can only increase the alignment. If you
> want to decrease it, you must additionally use the "packed"
> attribute, which gets rid of the default minimum alignment.
> Thus, it seems best to allow the ability to specify alignment on
> each member individually in the alien API, as well.
> Also, while compiler writers may not use _completely_ random
> alignment rules, it almost seems that way on PPC. A double will
> have 8-byte alignment iff it is the first element in the struct. In
> any other position, it will only force 4-byte alignment.