[PATCH] Fix ada inferior-data cleanup

[Joel Brobecker]

> 'struct ada_inferior_data' is registered to per-inferior-data with
> cleanup ada_inferior_data_cleanup, which means the data will be
> destroyed when the inferior exits.  It is unnecessary to call
> observer_attach_inferior_exit to do cleanups again.

Can you explain where the data actually gets destroyed? I've been
going through the code, and I just can't find where this would be
happening. Adding a debug trace confirms that the cleanup routine
never gets called if you remeove the inferior-exit observer.

> Regression tested by "make check RUNTESTFLAGS='--directory=gdb.ada'"
> on x86 Fedora 16 linux.
> 
> gdb:
> 
> 2013-10-26  Yao Qi  <yao@codesourcery.com>
> 
> 	* ada-lang.c (ada_inferior_data_cleanup): Don't get data from
> 	inferior_data.  Don't check NULL.  Free 'arg'.
> 	(ada_inferior_exit): Remove.
> 	(_initialize_ada_language): Don't call
> 	observer_attach_inferior_exit.
> ---
>  gdb/ada-lang.c |   17 +----------------
>  1 files changed, 1 insertions(+), 16 deletions(-)
> 
> diff --git a/gdb/ada-lang.c b/gdb/ada-lang.c
> index 75f9fe8..600f835 100644
> --- a/gdb/ada-lang.c
> +++ b/gdb/ada-lang.c
> @@ -336,11 +336,7 @@ static const struct inferior_data *ada_inferior_data;
>  static void
>  ada_inferior_data_cleanup (struct inferior *inf, void *arg)
>  {
> -  struct ada_inferior_data *data;
> -
> -  data = inferior_data (inf, ada_inferior_data);
> -  if (data != NULL)
> -    xfree (data);
> +  xfree (arg);
>  }
>  
>  /* Return our inferior data for the given inferior (INF).
> @@ -366,16 +362,6 @@ get_ada_inferior_data (struct inferior *inf)
>    return data;
>  }
>  
> -/* Perform all necessary cleanups regarding our module's inferior data
> -   that is required after the inferior INF just exited.  */
> -
> -static void
> -ada_inferior_exit (struct inferior *inf)
> -{
> -  ada_inferior_data_cleanup (inf, NULL);
> -  set_inferior_data (inf, ada_inferior_data, NULL);
> -}
> -
>                          /* Utilities */
>  
>  /* If TYPE is a TYPE_CODE_TYPEDEF type, return the target type after
> @@ -12958,7 +12944,6 @@ With an argument, catch only exceptions with the given name."),
>       NULL, xcalloc, xfree);
>  
>    /* Setup per-inferior data.  */
> -  observer_attach_inferior_exit (ada_inferior_exit);
>    ada_inferior_data
>      = register_inferior_data_with_cleanup (NULL, ada_inferior_data_cleanup);
>  }
> -- 
> 1.7.7.6

-- 
Joel