Re: [PATCH] adjust warning_n() to take uhwi (PR 84207)

[David Malcolm <dmalcolm at redhat dot com>]

On Tue, 2018-02-13 at 15:37 -0700, Martin Sebor wrote:
> On 02/13/2018 01:59 PM, Manuel López-Ibáñez wrote:
> > 
> > 
> > On 13 Feb 2018 5:58 pm, "Martin Sebor" <msebor@gmail.com
> > <mailto:msebor@gmail.com>> wrote:
> > 
> > 
> >     I wanted to make the _n() functions like warning_n() more
> >     robust by letting them accept a tree argument (as well as
> >     offset_int and wide_int) in addition to HOST_WIDE_INT but
> >     I can't do it if they can't work with these types.
> > 
> > 
> > There must be a tree-diagnostics.c where you can add those
> > functions and
> > then call the general diagnostic functions. Same for RTL.
> 
> I don't see how to do that.
> 
> Here's a sketch of what I tried to do:
> 
>    struct IntegerConverter
>    {
>      union {
>        tree t;
>        unsigned HOST_WIDE_INT hwi;
>        // buffer for offset_int, wide_int, etc.
>      } value;
> 
>      IntegerConverter (tree t)
>      {
>        value.t = t;
>      }
> 
>      IntegerConverter (unsigned HOST_WIDE_INT x)
>      {
>        value.x = x;
>      }
> 
>      ...
>    };
> 
>    void error_n (int, const IntegerConverter &, const char*, ...);
>    ...
> 
> With that, the call
> 
>    error_n (loc, t, "%E thing", "%E things", t);
> 
> works when t is a tree, and the call to the same function
> 
>    error_n (loc, i, "%wu thing", "%wu things", i);
> 
> also works when i is a HOST_WIDE_INT.  I chose this approach
> to avoid introducing additional overloads of the error_n()
> functions.

Why can't you simply introduce a tree-diagnostic.h and tree-
diagnostic.c and put overloads there?

In diagnostic.c the various _n all use diagnostic_n_impl, which
ultimately calls out to 
  ngettext (singular_gmsgid, plural_gmsgid, n)
so there would presumably be an analogous "diagnostic_n_hwi_impl" (or
somesuch) function there to do the same thing.

That would keep the tree stuff separated from the rest of the
diagnostics subsystem.

Or am I missing something?

Hope this is constructive
Dave

> > Note that pretty-printer.c works in the same way.
> 
> It works that way for arguments passed through the ellipsis.
> I was trying to use tree (indirectly) in the signature of
> the _n() functions and for that I need "tree.h" etc. in
> diagnostic-core.h and be able to call functions from
> the header in diagnostic-core.c.  I suppose I could make
> the calls indirectly somehow but I can't avoid including
> GCC headers in diagnostic-core.h.
> 
> Martin
>