Re: g++ 3.1 EH broken for irix6.5

[kenner at vlsi1 dot ultra dot nyu dot edu (Richard Kenner)]

    > Well, the question then is how do you specify that the type should be
    > packed by not "under-aligned"?

    At the moment, you can't.  You can get very close with packed+aligned,
    but you have to know how much alignment to give the structure.

Exactly and that's the key point: you can't specify that alignment in a
portable way.

    I'll interpret this as "how can we disentangle them within the
    compiler" not "how can we disentagle them in the user accessible
    attributes".  The later isn't very interesting I don't think -- we've
    never seen a need for it before, and I wouldn't want to invent
    something just because.

Well it comes up quite often in Ada: there "packed" means just what it
says and the user does not expect unnecessary performance degradation due
to chosing a smaller-than-necessary alignment.

We can easily make this front-end-dependent, but it would be a shame to
be providing a feature to Ada users that C users can't take advantage of.

    The answer is probably to have the packed attribute also set
    TYPE_USER_ALIGN or DECL_USER_ALIGN or whatever is appropriate,
    possibly with an additional bit set to let the layout routines know
    that these alignments are to override ABI defaults rather than augment
    ABI defaults.

I don't follow.