diff --git a/src/mesa/main/varray.c b/src/mesa/main/varray.c
index 213b845c9ca..059bd0b7114 100644
--- a/src/mesa/main/varray.c
+++ b/src/mesa/main/varray.c
@@ -1153,6 +1153,30 @@ _mesa_VertexAttribDivisor(GLuint index, GLuint divisor)
 }
 
 
+unsigned
+_mesa_primitive_restart_index(const struct gl_context *ctx, GLenum ib_type)
+{
+   /* From the OpenGL 4.3 core specification, page 302:
+    * "If both PRIMITIVE_RESTART and PRIMITIVE_RESTART_FIXED_INDEX are
+    *  enabled, the index value determined by PRIMITIVE_RESTART_FIXED_INDEX
+    *  is used."
+    */
+   if (ctx->Array.PrimitiveRestartFixedIndex) {
+      switch (ib_type) {
+      case GL_UNSIGNED_BYTE:
+         return 0xff;
+      case GL_UNSIGNED_SHORT:
+         return 0xffff;
+      case GL_UNSIGNED_INT:
+         return 0xffffffff;
+      default:
+         assert(!"_mesa_primitive_restart_index: Invalid index buffer type.");
+      }
+   }
+
+   return ctx->Array.RestartIndex;
+}
+
 
 /**
  * Copy one client vertex array to another.
diff --git a/src/mesa/main/varray.h b/src/mesa/main/varray.h
index 904fa1bea8f..46e9dc49568 100644
--- a/src/mesa/main/varray.h
+++ b/src/mesa/main/varray.h
@@ -248,6 +248,8 @@ _mesa_PrimitiveRestartIndex(GLuint index);
 extern void GLAPIENTRY
 _mesa_VertexAttribDivisor(GLuint index, GLuint divisor);
 
+extern unsigned
+_mesa_primitive_restart_index(const struct gl_context *ctx, GLenum ib_type);
 
 extern void
 _mesa_copy_client_array(struct gl_context *ctx,