Hi Simon,

Some minor remarks below.

On Tue, Oct 10, 2023 at 04:39:59PM -0400, Simon Marchi wrote:
> From: Simon Marchi <simon.marchi@polymtl.ca>
> 
> A subsequent patch changes so_list to be linked using
> intrusive_list.  Iterating an intrusive_list yields some references to
> the list elements.  Convert some functions accepting so_list objects to
> take references, to make things easier and more natural.  Add const
> where possible and convenient.
> 
> Change-Id: Id5ab5339c3eb6432e809ad14782952d6a45806f3
> ---
>  gdb/breakpoint.c     |   5 +-
>  gdb/bsd-uthread.c    |  12 ++---
>  gdb/exec.c           |   4 +-
>  gdb/interps.c        |   4 +-
>  gdb/interps.h        |   8 +--
>  gdb/mi/mi-cmd-file.c |   2 +-
>  gdb/mi/mi-interp.c   |  26 ++++-----
>  gdb/mi/mi-interp.h   |   6 +--
>  gdb/nto-tdep.c       |   6 +--
>  gdb/nto-tdep.h       |   3 +-
>  gdb/observable.h     |   5 +-
>  gdb/progspace.h      |   4 +-
>  gdb/solib-aix.c      |  11 ++--
>  gdb/solib-darwin.c   |  23 ++++----
>  gdb/solib-dsbt.c     |   9 ++--
>  gdb/solib-frv.c      |   9 ++--
>  gdb/solib-rocm.c     |   8 +--
>  gdb/solib-svr4.c     |  35 ++++++------
>  gdb/solib-target.c   |  49 +++++++++--------
>  gdb/solib.c          | 126 +++++++++++++++++++++----------------------
>  gdb/solib.h          |   4 +-
>  gdb/solist.h         |  13 +++--
>  gdb/target-section.h |   2 +-
>  23 files changed, 183 insertions(+), 191 deletions(-)
> 
> diff --git a/gdb/mi/mi-interp.h b/gdb/mi/mi-interp.h
> index f9af61f0a571..781a8dc6f466 100644
> --- a/gdb/mi/mi-interp.h
> +++ b/gdb/mi/mi-interp.h
> @@ -60,8 +60,8 @@ class mi_interp final : public interp
>    void on_record_changed (inferior *inf, int started, const char *method,
>  			  const char *format) override;
>    void on_target_resumed (ptid_t ptid) override;
> -  void on_solib_loaded (so_list *so) override;
> -  void on_solib_unloaded (so_list *so) override;
> +  void on_solib_loaded (const so_list &so) override;
> +  void on_solib_unloaded (const so_list &so) override;

It is orthogonal to this change, but it would make sense for those
methods to be const as well.

Doing this requires interp::interp_ui_out to be const as well (as done
in attached patch).

>    void on_about_to_proceed () override;
>    void on_traceframe_changed (int tfnum, int tpnum) override;
>    void on_tsv_created (const trace_state_variable *tsv) override;
> diff --git a/gdb/observable.h b/gdb/observable.h
> index acb05e9b535c..5ed6ca547ce0 100644
> --- a/gdb/observable.h
> +++ b/gdb/observable.h
> @@ -99,13 +99,12 @@ extern observable<inferior */* parent_inf */, inferior */* child_inf */,
>  /* The shared library specified by SOLIB has been loaded.  Note that
>     when gdb calls this observer, the library's symbols probably
>     haven't been loaded yet.  */
> -extern observable<struct so_list */* solib */> solib_loaded;
> +extern observable<so_list &/* solib */> solib_loaded;

I am wondering, is there a reason to make the solib parameter const for
solib_unloaded but not for solib_loaded?  

Changing it to const seems to still compile just fine.  If down the line
an observer needs to modify the SO, the observer's signature can be
adjusted.

>  
>  /* The shared library SOLIB has been unloaded from program space PSPACE.
>     Note  when gdb calls this observer, the library's symbols have not
>     been unloaded yet, and thus are still available.  */
> -extern observable<struct program_space */* pspace */, struct so_list */* solib */>
> -  solib_unloaded;
> +extern observable<program_space *, const so_list &/* solib */> solib_unloaded;
>  
>  /* The symbol file specified by OBJFILE has been loaded.  */
>  extern observable<struct objfile */* objfile */> new_objfile;