diff --git a/dev/alpha_console.hh b/dev/alpha_console.hh
index 86ef021e9f..f63c6ad7e5 100644
--- a/dev/alpha_console.hh
+++ b/dev/alpha_console.hh
@@ -43,6 +43,7 @@ class BaseCPU;
 class SimConsole;
 class AlphaSystem;
 class SimpleDisk;
+class MemoryController;
 
 /**
  * Memory mapped interface to the system console. This device
diff --git a/dev/uart.hh b/dev/uart.hh
index 145b9ca9e6..78b1dc68e0 100644
--- a/dev/uart.hh
+++ b/dev/uart.hh
@@ -37,6 +37,7 @@
 #include "dev/io_device.hh"
 
 class SimConsole;
+class MemoryController;
 class Platform;
 
 const int RX_INT = 0x1;
diff --git a/dev/uart8250.hh b/dev/uart8250.hh
index 88abf8e242..63d1da3cf5 100644
--- a/dev/uart8250.hh
+++ b/dev/uart8250.hh
@@ -53,6 +53,7 @@
 #define IIR_LINE  0x06 /* Rx Line Status (highest priority)*/
 
 class SimConsole;
+class MemoryController;
 class Platform;
 
 class Uart8250 : public Uart