Change varobj to use value_ref_ptr

This changes varobj to use value_ref_ptr, allowing the removal of some
manual reference count management.

gdb/ChangeLog
2018-04-06  Tom Tromey  <tom@tromey.com>

	* varobj.h (struct varobj) <value>: Now a value_ref_ptr.
	* varobj.c (varobj_set_display_format, varobj_set_value)
	(install_default_visualizer, construct_visualizer)
	(install_new_value, ~varobj, varobj_get_value_type)
	(my_value_of_variable, varobj_editable_p): Update.
	* c-varobj.c (c_describe_child, c_value_of_variable)
	(cplus_number_of_children, cplus_describe_child): Update.
	* ada-varobj.c (ada_number_of_children, ada_name_of_child)
	(ada_path_expr_of_child, ada_value_of_child, ada_type_of_child)
	(ada_value_of_variable, ada_value_is_changeable_p): Update.

1 files changed, 8 insertions, 7 deletions

diff --git a/gdb/c-varobj.c b/gdb/c-varobj.c
index babda29..03656c0 100644
--- a/gdb/c-varobj.c
+++ b/gdb/c-varobj.c
@@ -286,7 +286,7 @@ c_describe_child (const struct varobj *parent, int index,
 		  std::string *cname, struct value **cvalue,
 		  struct type **ctype, std::string *cfull_expression)
 {
-  struct value *value = parent->value;
+  struct value *value = parent->value.get ();
   struct type *type = varobj_get_value_type (parent);
   std::string parent_expression;
   int was_ptr;
@@ -513,21 +513,22 @@ c_value_of_variable (const struct varobj *var,
 	  }
 	else
 	  {
-	    if (var->not_fetched && value_lazy (var->value))
+	    if (var->not_fetched && value_lazy (var->value.get ()))
 	      /* Frozen variable and no value yet.  We don't
 		 implicitly fetch the value.  MI response will
 		 use empty string for the value, which is OK.  */
 	      return std::string ();
 
 	    gdb_assert (varobj_value_is_changeable_p (var));
-	    gdb_assert (!value_lazy (var->value));
+	    gdb_assert (!value_lazy (var->value.get ()));
 	    
 	    /* If the specified format is the current one,
 	       we can reuse print_value.  */
 	    if (format == var->format)
 	      return var->print_value;
 	    else
-	      return varobj_value_get_print_value (var->value, format, var);
+	      return varobj_value_get_print_value (var->value.get (), format,
+						   var);
 	  }
       }
     }
@@ -579,7 +580,7 @@ cplus_number_of_children (const struct varobj *var)
       /* It is necessary to access a real type (via RTTI).  */
       if (opts.objectprint)
         {
-          value = var->value;
+          value = var->value.get ();
           lookup_actual_type = (TYPE_IS_REFERENCE (var->type)
 				|| TYPE_CODE (var->type) == TYPE_CODE_PTR);
         }
@@ -616,7 +617,7 @@ cplus_number_of_children (const struct varobj *var)
         {
 	  const struct varobj *parent = var->parent;
 
-	  value = parent->value;
+	  value = parent->value.get ();
 	  lookup_actual_type = (TYPE_IS_REFERENCE (parent->type)
 				|| TYPE_CODE (parent->type) == TYPE_CODE_PTR);
         }
@@ -724,7 +725,7 @@ cplus_describe_child (const struct varobj *parent, int index,
   if (opts.objectprint)
     lookup_actual_type = (TYPE_IS_REFERENCE (var->type)
 			  || TYPE_CODE (var->type) == TYPE_CODE_PTR);
-  value = var->value;
+  value = var->value.get ();
   type = varobj_get_value_type (var);
   if (cfull_expression)
     parent_expression