Re: [RFA 2/2] Change install_breakpoint to take a std::unique_ptr

[Pedro Alves <palves@redhat.com>]

On 08/20/2017 02:54 PM, Tom Tromey wrote:
> @@ -8540,8 +8540,10 @@ init_catchpoint (struct breakpoint *b,
>  }
>  
>  void
> -install_breakpoint (int internal, struct breakpoint *b, int update_gll)
> +install_breakpoint (int internal, std::unique_ptr<breakpoint> &&arg, int update_gll)
>  {
> +  breakpoint *b = arg.release ();
> +
>    add_to_breakpoint_chain (b);

I think we should defer .release() until the ownership
transfer actually happened, for stronger exception safety.

I.e., either:

    add_to_breakpoint_chain (arg.get ());
    breakpoint *b = arg.release ();

or change add_to_breakpoint_chain to take an rvalue-ref unique_ptr
too, and return the raw breakpoint, and then write here:

    breakpoint *b = add_to_breakpoint_chain (std::move (arg));

Some spots were/are already only doing the release after
adding the breakpoint to the chain, but not all.  See e.g.,
set_raw_breakpoint.

The latter approach is my preferred for enforcing the pattern.

Otherwise both patches LGTM.

Thanks,
Pedro Alves