Remove target_close

  I noticed that target_close is only called in two places:
solib-svr4.c, and target_ops_ref_policy::decref.

This patch fixes the former by changing target_bfd_reopen to return a
target_ops_up and then fixing the sole caller.  Then it removes
target_close by inlining its body into the decref method.

The advantage of this approach is that targets are now automatically
managed.

Regression tested on x86-64 Fedora 38.
---
 gdb/bfd-target.c |  4 ++--
 gdb/bfd-target.h |  2 +-
 gdb/solib-svr4.c | 16 ++++++----------
 gdb/target.c     | 25 ++++++++++---------------
 gdb/target.h     |  9 ---------
 5 files changed, 19 insertions(+), 37 deletions(-)
  

Tom Tromey <tom@tromey.com> writes:

> I noticed that target_close is only called in two places:
> solib-svr4.c, and target_ops_ref_policy::decref.
>
> This patch fixes the former by changing target_bfd_reopen to return a
> target_ops_up and then fixing the sole caller.  Then it removes
> target_close by inlining its body into the decref method.
>
> The advantage of this approach is that targets are now automatically
> managed.
>
> Regression tested on x86-64 Fedora 38.
> ---
>  gdb/bfd-target.c |  4 ++--
>  gdb/bfd-target.h |  2 +-
>  gdb/solib-svr4.c | 16 ++++++----------
>  gdb/target.c     | 25 ++++++++++---------------
>  gdb/target.h     |  9 ---------
>  5 files changed, 19 insertions(+), 37 deletions(-)
>
> diff --git a/gdb/bfd-target.c b/gdb/bfd-target.c
> index 6b8a839b286..9e1b980957c 100644
> --- a/gdb/bfd-target.c
> +++ b/gdb/bfd-target.c
> @@ -94,10 +94,10 @@ target_bfd::target_bfd (const gdb_bfd_ref_ptr &abfd)
>  {
>  }
>  
> -target_ops *
> +target_ops_up
>  target_bfd_reopen (const gdb_bfd_ref_ptr &abfd)
>  {
> -  return new target_bfd (abfd);
> +  return target_ops_up (new target_bfd (abfd));
>  }
>  
>  void
> diff --git a/gdb/bfd-target.h b/gdb/bfd-target.h
> index d77f0367fd5..eb33374c6ea 100644
> --- a/gdb/bfd-target.h
> +++ b/gdb/bfd-target.h
> @@ -25,6 +25,6 @@
>  struct target_ops;
>  
>  /* Given an existing BFD, re-open it as a "struct target_ops".  */
> -struct target_ops *target_bfd_reopen (const gdb_bfd_ref_ptr &bfd);
> +target_ops_up target_bfd_reopen (const gdb_bfd_ref_ptr &bfd);
>  
>  #endif
> diff --git a/gdb/solib-svr4.c b/gdb/solib-svr4.c
> index 0ef83726d62..f1fa437e31a 100644
> --- a/gdb/solib-svr4.c
> +++ b/gdb/solib-svr4.c
> @@ -2425,7 +2425,7 @@ enable_break (struct svr4_info *info, int from_tty)
>        CORE_ADDR load_addr = 0;
>        int load_addr_found = 0;
>        int loader_found_in_list = 0;
> -      struct target_ops *tmp_bfd_target;
> +      target_ops_up tmp_bfd_target;

Might as well move this declaration down to where tmp_bfd_target is
first assigned.

Otherwise, LGTM.

Approved-By: Andrew Burgess <aburgess@redhat.com>

Thanks,
Andrew

>  
>        sym_addr = 0;
>  
> @@ -2482,8 +2482,8 @@ enable_break (struct svr4_info *info, int from_tty)
>  	    if (addr_bit < (sizeof (CORE_ADDR) * HOST_CHAR_BIT))
>  	      {
>  		CORE_ADDR space_size = (CORE_ADDR) 1 << addr_bit;
> -		CORE_ADDR tmp_entry_point = exec_entry_point (tmp_bfd.get (),
> -							      tmp_bfd_target);
> +		CORE_ADDR tmp_entry_point
> +		  = exec_entry_point (tmp_bfd.get (), tmp_bfd_target.get ());
>  
>  		gdb_assert (load_addr < space_size);
>  
> @@ -2512,7 +2512,8 @@ enable_break (struct svr4_info *info, int from_tty)
>  					inferior_ptid, target_gdbarch ());
>  
>  	  load_addr = (regcache_read_pc (regcache)
> -		       - exec_entry_point (tmp_bfd.get (), tmp_bfd_target));
> +		       - exec_entry_point (tmp_bfd.get (),
> +					   tmp_bfd_target.get ()));
>  	}
>  
>        if (!loader_found_in_list)
> @@ -2564,12 +2565,7 @@ enable_break (struct svr4_info *info, int from_tty)
>  	   target, this will always produce an unrelocated value.  */
>  	sym_addr = gdbarch_convert_from_func_ptr_addr (target_gdbarch (),
>  						       sym_addr,
> -						       tmp_bfd_target);
> -
> -      /* We're done with both the temporary bfd and target.  Closing
> -	 the target closes the underlying bfd, because it holds the
> -	 only remaining reference.  */
> -      target_close (tmp_bfd_target);
> +						       tmp_bfd_target.get ());
>  
>        if (sym_addr != 0)
>  	{
> diff --git a/gdb/target.c b/gdb/target.c
> index fecbc89d3ca..16f43d072cd 100644
> --- a/gdb/target.c
> +++ b/gdb/target.c
> @@ -1173,7 +1173,16 @@ target_ops_ref_policy::decref (target_ops *t)
>      {
>        if (t->stratum () == process_stratum)
>  	connection_list_remove (as_process_stratum_target (t));
> -      target_close (t);
> +
> +      for (inferior *inf : all_inferiors ())
> +	gdb_assert (!inf->target_is_pushed (t));
> +
> +      fileio_handles_invalidate_target (t);
> +
> +      t->close ();
> +
> +      if (targetdebug)
> +	gdb_printf (gdb_stdlog, "closing target\n");
>      }
>  }
>  
> @@ -3752,20 +3761,6 @@ debug_target::info () const
>  
>  
>  
> -void
> -target_close (struct target_ops *targ)
> -{
> -  for (inferior *inf : all_inferiors ())
> -    gdb_assert (!inf->target_is_pushed (targ));
> -
> -  fileio_handles_invalidate_target (targ);
> -
> -  targ->close ();
> -
> -  if (targetdebug)
> -    gdb_printf (gdb_stdlog, "target_close ()\n");
> -}
> -
>  int
>  target_thread_alive (ptid_t ptid)
>  {
> diff --git a/gdb/target.h b/gdb/target.h
> index 5f9a2a2d97a..6ae400e2cc2 100644
> --- a/gdb/target.h
> +++ b/gdb/target.h
> @@ -1410,15 +1410,6 @@ extern target_ops *get_dummy_target ();
>  
>  extern const char *target_shortname ();
>  
> -/* Does whatever cleanup is required for a target that we are no
> -   longer going to be calling.  This routine is automatically always
> -   called after popping the target off the target stack - the target's
> -   own methods are no longer available through the target vector.
> -   Closing file descriptors and freeing all memory allocated memory are
> -   typical things it should do.  */
> -
> -void target_close (struct target_ops *targ);
> -
>  /* Find the correct target to use for "attach".  If a target on the
>     current stack supports attaching, then it is returned.  Otherwise,
>     the default run target is returned.  */
> -- 
> 2.41.0
  

>>>>> "Andrew" == Andrew Burgess <aburgess@redhat.com> writes:

>> -      struct target_ops *tmp_bfd_target;
>> +      target_ops_up tmp_bfd_target;

Andrew> Might as well move this declaration down to where tmp_bfd_target is
Andrew> first assigned.

I tried that originally but there is a 'goto' that then causes a
compilation error.

Andrew> Approved-By: Andrew Burgess <aburgess@redhat.com>

Thanks.

Tom