[llvm] r190773 - Implement function prefix data as an IR feature.

[Peter Collingbourne]

On Mon, Sep 23, 2013 at 01:14:05PM -0700, Richard Mitton wrote:
> Hi,
>
> I have a small question about this -
>
> Why does the prefix data have to begin with a jump?
> Couldn't you just make the entry point label appear after the prefix  
> data? And then use negative offsets to access it given the function's  
> address? It seems like the jump adds a performance hit which isn't 
> needed.
>
> e.g.
>
> .word 0x1234 // prefix data
> myfunction:
>     push rbp
>     // etc
>     ret

Hi Richard,

I answered this question here:
http://lists.cs.uiuc.edu/pipermail/llvmdev/2013-July/063950.html

In general I hope to include an FAQ in the blog post which will answer
these sorts of questions.

Thanks,
-- 
Peter