PR c++/85033

	* semantics.c (finish_offsetof): Don't allow CONST_DECLs.

	* g++.dg/ext/builtin-offsetof2.C: New test.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@258801 138bc75d-0d04-0410-961f-82ee72b054a4

Author: mpolacek

gcc/cp/ChangeLog

@@ -1,3 +1,8 @@
+2018-03-23  Marek Polacek  <[email protected]>
+
+	PR c++/85033
+	* semantics.c (finish_offsetof): Don't allow CONST_DECLs.
+
 2018-03-23  Alexandre Oliva <[email protected]>
 
 	PR c++/71251

gcc/cp/semantics.c

@@ -4072,6 +4072,11 @@ finish_offsetof (tree object_ptr, tree expr, location_t loc)
 	}
       return error_mark_node;
     }
+  if (TREE_CODE (expr) == CONST_DECL)
+    {
+      error ("cannot apply %<offsetof%> to an enumerator %qD", expr);
+      return error_mark_node;
+    }
   if (REFERENCE_REF_P (expr))
     expr = TREE_OPERAND (expr, 0);
   if (!complete_type_or_else (TREE_TYPE (TREE_TYPE (object_ptr)), object_ptr))

gcc/testsuite/ChangeLog

@@ -1,3 +1,8 @@
+2018-03-23  Marek Polacek  <[email protected]>
+
+	PR c++/85033
+	* g++.dg/ext/builtin-offsetof2.C: New test.
+
 2018-03-23  Eric Botcazou  <[email protected]>
 
 	PR debug/85020

gcc/testsuite/g++.dg/ext/builtin-offsetof2.C

@@ -0,0 +1,7 @@
+// PR c++/85033
+
+struct S {
+  enum { E };
+};
+
+int b = __builtin_offsetof(S, E); // { dg-error "cannot apply .offsetof. to an enumerator" }