PR c++/55203

c-family/
	* c-common.c (c_common_attribute_table): Add warn_unused.
	(handle_warn_unused_attribute): New.
cp/
	* init.c (build_aggr_init): Check for warn_unused attribute.
	* decl.c (poplevel): Likewise.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@200941 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 24 insertions, 0 deletions

diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c
index 61300cd05c7..970f9f20a08 100644
--- a/gcc/c-family/c-common.c
+++ b/gcc/c-family/c-common.c
@@ -368,6 +368,7 @@ static tree handle_optimize_attribute (tree *, tree, tree, int, bool *);
 static tree ignore_attribute (tree *, tree, tree, int, bool *);
 static tree handle_no_split_stack_attribute (tree *, tree, tree, int, bool *);
 static tree handle_fnspec_attribute (tree *, tree, tree, int, bool *);
+static tree handle_warn_unused_attribute (tree *, tree, tree, int, bool *);
 
 static void check_function_nonnull (tree, int, tree *);
 static void check_nonnull_arg (void *, tree, unsigned HOST_WIDE_INT);
@@ -738,6 +739,8 @@ const struct attribute_spec c_common_attribute_table[] =
      The name contains space to prevent its usage in source code.  */
   { "fn spec",	 	      1, 1, false, true, true,
 			      handle_fnspec_attribute, false },
+  { "warn_unused",            0, 0, false, false, false,
+			      handle_warn_unused_attribute, false },
   { NULL,                     0, 0, false, false, false, NULL, false }
 };
 
@@ -7950,6 +7953,27 @@ handle_fnspec_attribute (tree *node ATTRIBUTE_UNUSED, tree ARG_UNUSED (name),
   return NULL_TREE;
 }
 
+/* Handle a "warn_unused" attribute; arguments as in
+   struct attribute_spec.handler.  */
+
+static tree
+handle_warn_unused_attribute (tree *node, tree name,
+			      tree args ATTRIBUTE_UNUSED,
+			      int flags ATTRIBUTE_UNUSED, bool *no_add_attrs)
+{
+  if (TYPE_P (*node))
+    /* Do nothing else, just set the attribute.  We'll get at
+       it later with lookup_attribute.  */
+    ;
+  else
+    {
+      warning (OPT_Wattributes, "%qE attribute ignored", name);
+      *no_add_attrs = true;
+    }
+
+  return NULL_TREE;
+}
+
 /* Handle a "returns_twice" attribute; arguments as in
    struct attribute_spec.handler.  */