[patch][PR10367] Fix the design of GlobalAlias

[Reid Kleckner]

On Tue, May 13, 2014 at 10:31 AM, Rafael Espíndola <
rafael.espindola at gmail.com> wrote:

> > It was nice that `Alignment` was packed in here before.
> >
> > I wonder if it's worth the complexity of storing `Alignment` in
> > `GlobalValue`, even though it's only valid for `GlobalObject`?  Maybe
> > using the `Value::SubclassData` model?  I'm not sure how much this
> > bloat matters (1M globals => 8 MB).
>
> Probably. This revised patch fixes the style issue and uses the parent
> padding bits.
>
> The sizes I get with the patch on x86_64 are:
>
> Constant:       56
> GlobalValue:    64
> GlobalObject:   88
> GlobalVariable: 112
> Function:       152
>
> Without the patch they are
>
> Constant:       56
> GlobalValue:    88
> GlobalObject:   X
> GlobalVariable: 112
> Function:       152
>
> Cheers,
> Rafael
>

The first patch looks good, I'm just opening the second patch.

I think previously you suggested splitting this into GlobalName /
GlobalValue instead of GlobalValue / GlobalObject.  I kind of liked
GlobalName.  Any reason to split this way instead?  Does it avoid excessive
API churn?
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