RFC: Support non-standard extension (call via casted function pointer)

[Jeff Law]

On 01/28/2016 03:11 AM, Florian Weimer wrote:
> On 01/27/2016 04:17 PM, Richard Biener wrote:
>
>> We are trying to support
>>
>> t.c
>> ---
>> void *foo();
>>
>> int bar()
>> {
>>    return ((int (*)())foo) ();
>> }
>>
>> t2.c
>> -----
>> int foo () { return 0; }
>>
>> thus doing a direct call to a function with a (wrong) prototype via a function
>> pointer cast to the correct type and having a matching implementation of
>> that function elsewhere.
>
> I suspect Ada needs something like this already.  I expect the following
> to work (although it is quite hideous).
Yes.  I'm pretty sure there's a BZ to this effect already in the 
gcc-bugs database.

I know someone (probably Andreas) with some work was able to get GCC 
working with Ada.  However, they didn't push to get all those changes 
upstreamed.

It's one of the reasons why I think we should at least explore a more a 
solution within GCC iteslf.

Jeff