[PATCH 7/7] Add ATTRIBUTE_UNUSED_RESULT to ref_ptr::release

[Tom Tromey <tromey@adacore.com>]

This applies ATTRIBUTE_UNUSED_RESULT to ref_ptr::release and updates a
few spots to comply.  I believe one use in install_default_visualizer
was in error, fixed by this patch.

2019-02-27  Tom Tromey  <tromey@adacore.com>

	* varobj.c (update_dynamic_varobj_children): Update.
	(install_default_visualizer): Use reset, not release.
	* value.c (set_internalvar): Update.
	* dwarf2loc.c (value_of_dwarf_reg_entry): Update.
	* common/gdb_ref_ptr.h (class ref_ptr) <release>: Add
	ATTRIBUTE_UNUSED_RESULT.
---
 gdb/ChangeLog            |  9 +++++++++
 gdb/common/gdb_ref_ptr.h |  2 +-
 gdb/dwarf2loc.c          |  3 +--
 gdb/value.c              | 10 +++++-----
 gdb/varobj.c             |  4 ++--
 5 files changed, 18 insertions(+), 10 deletions(-)

diff --git a/gdb/common/gdb_ref_ptr.h b/gdb/common/gdb_ref_ptr.h
index b104556cc5f..c31c9a2e58b 100644
--- a/gdb/common/gdb_ref_ptr.h
+++ b/gdb/common/gdb_ref_ptr.h
@@ -135,7 +135,7 @@ class ref_ptr
   /* Return this instance's referent, and stop managing this
      reference.  The caller is now responsible for the ownership of
      the reference.  */
-  T *release ()
+  ATTRIBUTE_UNUSED_RESULT T *release ()
   {
     T *result = m_obj;
 
diff --git a/gdb/dwarf2loc.c b/gdb/dwarf2loc.c
index 9c974a11133..29d289b4d0c 100644
--- a/gdb/dwarf2loc.c
+++ b/gdb/dwarf2loc.c
@@ -1472,9 +1472,8 @@ value_of_dwarf_reg_entry (struct type *type, struct frame_info *frame,
 					       target_type, caller_frame,
 					       caller_per_cu);
 
-  release_value (target_val).release ();
   val = allocate_computed_value (type, &entry_data_value_funcs,
-				 target_val /* closure */);
+				 release_value (target_val).release ());
 
   /* Copy the referencing pointer to the new computed value.  */
   memcpy (value_contents_raw (val), value_contents_raw (outer_val),
diff --git a/gdb/value.c b/gdb/value.c
index 95b6a56f32e..50e47a936aa 100644
--- a/gdb/value.c
+++ b/gdb/value.c
@@ -2274,20 +2274,20 @@ set_internalvar (struct internalvar *var, struct value *val)
 
     default:
       new_kind = INTERNALVAR_VALUE;
-      new_data.value = value_copy (val);
-      new_data.value->modifiable = 1;
+      struct value *copy = value_copy (val);
+      copy->modifiable = 1;
 
       /* Force the value to be fetched from the target now, to avoid problems
 	 later when this internalvar is referenced and the target is gone or
 	 has changed.  */
-      if (value_lazy (new_data.value))
-       value_fetch_lazy (new_data.value);
+      if (value_lazy (copy))
+	value_fetch_lazy (copy);
 
       /* Release the value from the value chain to prevent it from being
 	 deleted by free_all_values.  From here on this function should not
 	 call error () until new_data is installed into the var->u to avoid
 	 leaking memory.  */
-      release_value (new_data.value).release ();
+      new_data.value = release_value (copy).release ();
 
       /* Internal variables which are created from values with a dynamic
          location don't need the location property of the origin anymore.
diff --git a/gdb/varobj.c b/gdb/varobj.c
index b03307068f3..3715bb6a7df 100644
--- a/gdb/varobj.c
+++ b/gdb/varobj.c
@@ -760,7 +760,7 @@ update_dynamic_varobj_children (struct varobj *var,
 	  /* Release vitem->value so its lifetime is not bound to the
 	     execution of a command.  */
 	  if (item != NULL && item->value != NULL)
-	    release_value (item->value).release ();
+	    item->value = release_value (item->value).release ();
 	}
 
       if (item == NULL)
@@ -1127,7 +1127,7 @@ install_default_visualizer (struct varobj *var)
 	}
 
       if (pretty_printer == Py_None)
-	pretty_printer.release ();
+	pretty_printer.reset (nullptr);
   
       install_visualizer (var->dynamic, NULL, pretty_printer.release ());
     }
-- 
2.20.1