re PR c++/62017 (AddressSanitizer reports *-buffer-overflow in destructor when…

re PR c++/62017 (AddressSanitizer reports *-buffer-overflow in destructor when multiple virtual inheritance is used)

	PR c++/62017
	* decl.c (begin_destructor_body): Only clobber the as-base part of
	*this.

From-SVN: r215427

gcc/cp/ChangeLog

+2014-09-20  Jason Merrill  <jason@redhat.com>
+
+	PR c++/62017
+	* decl.c (begin_destructor_body): Only clobber the as-base part of
+	*this.
+
 2014-09-19  Jason Merrill  <jason@redhat.com>
 
 	PR c++/61392

gcc/cp/decl.c

@@ -13808,10 +13808,12 @@ begin_destructor_body (void)
 
       /* Insert a cleanup to let the back end know that the object is dead
 	 when we exit the destructor, either normally or via exception.  */
-      tree clobber = build_constructor (current_class_type, NULL);
+      tree btype = CLASSTYPE_AS_BASE (current_class_type);
+      tree clobber = build_constructor (btype, NULL);
       TREE_THIS_VOLATILE (clobber) = true;
-      tree exprstmt = build2 (MODIFY_EXPR, current_class_type,
-			      current_class_ref, clobber);
+      tree bref = build_nop (build_reference_type (btype), current_class_ptr);
+      bref = convert_from_reference (bref);
+      tree exprstmt = build2 (MODIFY_EXPR, btype, bref, clobber);
       finish_decl_cleanup (NULL_TREE, exprstmt);
 
       /* And insert cleanups for our bases and members so that they