Re: [PATCH v5 03/15] gdb, gdbserver: support dlmopen()

[Kevin Buettner <kevinb@redhat.com>]

On Mon, 27 Jun 2022 12:55:57 +0000
"Metzger, Markus T" <markus.t.metzger@intel.com> wrote:

> Thanks for your review, Kevin,
[...]
> >I was puzzled for a while by the uses of std:swap() in the above
> >snippets of code.  I checked the rest of the GDB sources and found
> >that (at least in GDB) this is not a common idiom.  I'd appreciate
> >it if you could add a few lines of explanation for at least one
> >of them.  
> 
> Do those comments help?

Yes!  Thanks for adding them.

Kevin

> 
> diff --git a/gdb/solib-svr4.c b/gdb/solib-svr4.c
> index 1f2abcf16ef..b231888b001 100644
> --- a/gdb/solib-svr4.c
> +++ b/gdb/solib-svr4.c
> @@ -1346,6 +1346,10 @@ svr4_current_sos_direct (struct svr4_info *info)
>           && (library_list.solib_lists[0] == nullptr))
>         library_list.solib_lists.erase (0);
>  
> +      /* Replace the (empty) solib_lists in INFO with the one generated
> +        from the target.  We don't want to copy it on assignment and then
> +        delete the original afterwards, so let's just swap the
> +        internals.  */
>        std::swap (info->solib_lists, library_list.solib_lists);
>        return;
>      }
> @@ -1872,7 +1876,11 @@ solist_update_incremental (svr4_info *info, CORE_ADDR debug_base,
>        if (!svr4_current_sos_via_xfer_libraries (&library_list, annex))
>         return 0;
>  
> -      /* We expect gdbserver to provide updates for the namespace that
> +      /* Get the so list from the target.  We replace the list in the
> +         target response so we can easily check that the response only
> +         covers one namespace.
> +
> +        We expect gdbserver to provide updates for the namespace that
>          contains LM, which whould be this namespace...  */
>        so_list *sos = nullptr;
>        if (library_list.solib_lists.find (debug_base)