Re: [Qemu-devel] [RFC PATCH v2 1/2] utils: Add helper to read arm MIDR_EL1 register

[Richard Henderson]

On 08/18/2016 07:14 AM, Peter Maydell wrote:
> On 18 August 2016 at 15:04, Richard Henderson <address@hidden> wrote:
> > or (2) ifunc
>
> While we're on the subject, can somebody explain to me why we
> use ifuncs at all? I couldn't work out why it would be better than
> just using a straightforward function pointer -- when I tried single
> stepping through things the ifunc approach still seemed to indirect
> through some table or other so it wasn't actually resolving to
> a direct function call anyway.

No reason, I suppose.

It's particularly helpful for libraries, where we don't really want the 
overhead of the initialization when it's not used.

But (1) we don't have many of these and (2) we really don't care *that* much 
about startup time.

So a simple function pointer initialized by a constructor has the same effect.


r~