[LLVMdev] [RFC] NoBuiltin Attribute

[Chris Lattner]

On Feb 20, 2013, at 1:35 PM, David Blaikie <dblaikie at gmail.com> wrote:

> 
> 
> 
> On Wed, Feb 20, 2013 at 12:39 PM, Chris Lattner <clattner at apple.com> wrote:
> On Feb 20, 2013, at 8:40 AM, David Blaikie <dblaikie at gmail.com> wrote:
>> Sure, if you're willing to sacrifice the possible simplification of all indirect calls in any function that has even one nobuiltin requirement.
>> 
> 
> I don't understand what you mean by this.
>> 1) annotate calls
>> Pro: you can inline calls without pessimizing the function you inline into
>> Con: you pessimize all indirect calls in functions with at least one nobuiltin requirement
>> 
> Can you give an example illustrating the con?  I don't see how anything is pessimized with this approach.
> 
> 
> Yep, sorry - seems I added more confusion to this thread rather than less.
> 
> The only con I can see to the call-site annotation scheme is that you have to annotate all indirect calls (I assume there's some compile-time cost per thing you annotate so one would prefer to annotate fewer things - but probably a relatively small issue?) and then any direct call to the specific functions you care about.

There is no compile time cost to that, it is just writing a different pointer into a field.  The attribute sets are uniqued already.

-Chris

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