c-common.c (decl_attributes): Set TREE_USED on the object pointed to.

	* c-common.c (decl_attributes) [A_ALIAS]: Set TREE_USED on the
	object pointed to.

From-SVN: r33284

gcc/ChangeLog

+2000-04-20  Zack Weinberg  <zack@wolery.cumb.org>
+
+	* c-common.c (decl_attributes) [A_ALIAS]: Set TREE_USED on the
+	object pointed to.
+
 Thu Apr 20 14:19:18 MET DST 2000  Jan Hubicka  <jh@suse.cz>
 
 	* loop.c (emit_iv_add_mult):  Simplify it's input and emit

gcc/c-common.c

@@ -981,6 +981,8 @@ decl_attributes (node, attributes, prefix_attributes)
 		  break;
 		}
 	      id = get_identifier (TREE_STRING_POINTER (id));
+	      /* This counts as a use of the object pointed to.  */
+	      TREE_USED (id) = 1;
 
 	      if (TREE_CODE (decl) == FUNCTION_DECL)
 		DECL_INITIAL (decl) = error_mark_node;

gcc/testsuite/gcc.dg/20000419-2.c

+/* A static function with a global alias should not get 'defined but
+   not used' warnings.  Exposed by Linux kernel.  */
+/* { dg-do compile } */
+/* { dg-options "-Wall" } */
+
+extern void do_something (void);
+extern void do_something_else (void);
+
+static int
+init_foobar(void)  /* { dg-bogus "defined but not used" "not used warning" } */
+{
+  do_something();
+  do_something_else();
+  return 0;
+}
+
+int init_module(void) __attribute__((alias("init_foobar")));