[RFC] Fix for PR58201

[Jan Hubicka]

> On 09/04/2013 06:04 PM, Jan Hubicka wrote:
> > this is third fallout of my change to remove DECL_ARGUMENTS/DECL_RESULT for functions w/o
> > bodies I did not really anticipate.
> [...]
> > I would like to basically ask if it seems to make sense to go this route and
> > try to get rid of those declarations.
> 
> I'm currently working on a new target, ptx, which uses a
> pseudo-assembler where functions (even extern ones) need to be declared
> with their arguments and return types. With my current code I have to
> look at DECL_ARGUMENTS fairly late in the compilation. I'm not quite
> sure yet whether the change to delete them will break the backend.

How do you support K&R functions here?  My basic idea was that TYPE_ARG_TYPES
should give enough information about external function calling convention
anyone will ever need. I would hope that this will be sufficient for your
use, too, despite the fact you no longer have parameter names at hand
and you also lose info about external inline K&R-style delcared functions
that has been optimized out.

If not that indeed, you will not see DECL_ARGUMENTS for external function
anytime after cgraph_remove_unreachable_functions is called.

Honza