Re: [PATCH 13/13] Document "no debug info debugging" improvements

[Pedro Alves <palves@redhat.com>]

On 07/13/2017 12:09 PM, Pedro Alves wrote:

> I woke up thinking that mapping to unprototyped is the wrong
> equivalence -- that it'd be better to assume the function is
> prototyped, since that's how most C functions are written as
> nowadays.  Also, there's no such thing as an unprototyped
> function in C++.
> 
> Assuming prototyped would allow this, for example:
> 
>     float mult (float v1, float v2) { return v1 * v2; }
> 
>     (gdb) p (float) mult (2.0f, 3.0f)
>     $1 = 6
>     (gdb) p (float) mult ((float) 2, (float) 3)
>     $2 = 6
>     (gdb) p ((float (*) (float, float)) mult) (2, 3)
>     $3 = 6
> 
>     (gdb) ptype 2.0f
>     type = float
>     (gdb) ptype 2.0
>     type = double
> 
> If the function really is unprototyped, then you'd still be
> able to call it correctly via the function pointer cast syntax:
> 
>     float mult_noproto (v1, v2)
>        float v1, v2;
>     { return v1 * v2; }
> 
>     (gdb) p ((float (*) ()) mult_noproto) (2.0f, 3.0f)
>     $1 = 6
>     (gdb) p ((float (*) ()) mult_noproto) (2.0, 3.0)
>     $2 = 6
>     (gdb) p ((float (*) ()) mult_noproto) ((float) 2, (float) 3)
>     $3 = 6
> 
> I'll give this a try, and add those as tests to gdb.base/nodebug.exp.

This worked nicely, see below.

I'll tweak the docs, and send an updated patch.

Thanks,
Pedro Alves