Re: User directed Function Multiversioning via Function Overloading (issue5752064)

[Jason Merrill <jason at redhat dot com>]

On 10/30/2012 05:49 PM, Sriraman Tallam wrote:
> AFAIU, this should not be a problem. For duplicate declarations,
> duplicate_decls should merge them and they should never be seen here.
> Did I miss something?

With extern "C" functions you can have multiple declarations of the same 
function in different namespaces that are not duplicates, but still 
match.  And I can't think what that test is supposed to be catching, anyway.

> No, I thought about this but I did not want to handle this case in
> this iteration. The dispatcher is created only once and if more
> functions are declared later, they will not be dispatched atleast in
> this iteration.

I still think that instead of collecting the set of functions in 
overload resolution, they should be collected at declaration time and 
added to a vector in the cgraph information for use when generating the 
body of the dispatcher.

> You talked about doing the dispatcher
> building later, but I did it here since I am doing it only once.

I still don't think this is the right place for it.

> dispatcher_node does not have a body  until it is generated in
> cgraphunit.c, so cgraph does not mark this field before this is
> processed in cgraph_analyze_function.

That seems like something to address in your cgraph changes.

Jason