1 files changed, 10 insertions, 0 deletions
diff --git a/src/glsl/ir.h b/src/glsl/ir.h
index 9668c9439ad..7b83c2836ee 100644
--- a/src/glsl/ir.h
+++ b/src/glsl/ir.h
@@ -225,6 +225,7 @@ enum ir_variable_mode {
    ir_var_in,
    ir_var_out,
    ir_var_inout,
+   ir_var_system_value, /**< Ex: front-face, instance-id, etc. */
    ir_var_temporary	/**< Temporary variable generated during compilation. */
 };
 
@@ -295,6 +296,15 @@ public:
    unsigned invariant:1;
 
    /**
+    * Has this variable been used for reading or writing?
+    *
+    * Several GLSL semantic checks require knowledge of whether or not a
+    * variable has been used.  For example, it is an error to redeclare a
+    * variable as invariant after it has been used.
+    */
+   unsigned used:1;
+
+   /**
     * Storage class of the variable.
     *
     * \sa ir_variable_mode