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

Pedro Alves
2017-07-13T13:51:56Z

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