Re: [XEN PATCH 3/4] xen/include: add pure and const attributes

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

> It doesn't seem to me that __attribute_pure__ could be correctly used on
> pdx_to_pfn with GCC 7.1.0 for example.
> 
> So in conclusion, I think it is better to avoid __attribute_pure__ and
> use SAF-xx-safe or an alternative approach instead.

I was thinking that another option would be to introduce a macro "pure"
that is defined as __attribute_pure__ for GCC 9 or later and defined to
nothing for GCC 8 or older.