diff --git a/gcc/config/pdp11/pdp11.c b/gcc/config/pdp11/pdp11.c
index 2812e95..651b0cc 100644
--- a/gcc/config/pdp11/pdp11.c
+++ b/gcc/config/pdp11/pdp11.c
@@ -157,6 +157,10 @@ static rtx pdp11_function_value (const_tree, const_tree, bool);
 static rtx pdp11_libcall_value (enum machine_mode, const_rtx);
 static bool pdp11_function_value_regno_p (const unsigned int);
 static void pdp11_trampoline_init (rtx, tree, rtx);
+static rtx pdp11_function_arg (CUMULATIVE_ARGS *, enum machine_mode,
+			       const_tree, bool);
+static void pdp11_function_arg_advance (CUMULATIVE_ARGS *,
+					enum machine_mode, const_tree, bool);
 
 /* Initialize the GCC target structure.  */
 #undef TARGET_ASM_BYTE_OP
@@ -189,6 +193,11 @@ static void pdp11_trampoline_init (rtx, tree, rtx);
 #undef TARGET_RTX_COSTS
 #define TARGET_RTX_COSTS pdp11_rtx_costs
 
+#undef TARGET_FUNCTION_ARG
+#define TARGET_FUNCTION_ARG pdp11_function_arg
+#undef TARGET_FUNCTION_ARG_ADVANCE
+#define TARGET_FUNCTION_ARG_ADVANCE pdp11_function_arg_advance
+
 #undef TARGET_RETURN_IN_MEMORY
 #define TARGET_RETURN_IN_MEMORY pdp11_return_in_memory
 
@@ -1834,3 +1843,42 @@ pdp11_trampoline_init (rtx m_tramp, tree fndecl, rtx chain_value)
   emit_move_insn (mem, GEN_INT (0x0058));
   emit_move_insn (mem, fnaddr);
 }
+
+/* Worker function for TARGET_FUNCTION_ARG.
+
+   Determine where to put an argument to a function.
+   Value is zero to push the argument on the stack,
+   or a hard register in which to store the argument.
+
+   MODE is the argument's machine mode.
+   TYPE is the data type of the argument (as a tree).
+    This is null for libcalls where that information may
+    not be available.
+   CUM is a variable of type CUMULATIVE_ARGS which gives info about
+    the preceding args and about the function being called.
+   NAMED is nonzero if this argument is a named parameter
+    (otherwise it is an extra parameter matching an ellipsis).  */
+
+static rtx
+pdp11_function_arg (CUMULATIVE_ARGS *cum ATTRIBUTE_UNUSED,
+		    enum machine_mode mode ATTRIBUTE_UNUSED,
+		    const_tree type ATTRIBUTE_UNUSED,
+		    bool named ATTRIBUTE_UNUSED)
+{
+  return NULL_RTX;
+}
+
+/* Worker function for TARGET_FUNCTION_ARG_ADVANCE.
+
+   Update the data in CUM to advance over an argument of mode MODE and
+   data type TYPE.  (TYPE is null for libcalls where that information
+   may not be available.)  */
+
+static void
+pdp11_function_arg_advance (CUMULATIVE_ARGS *cum, enum machine_mode mode,
+			    const_tree type, bool named ATTRIBUTE_UNUSED)
+{
+  *cum += (mode != BLKmode
+	   ? GET_MODE_SIZE (mode)
+	   : int_size_in_bytes (type));
+}
diff --git a/gcc/config/pdp11/pdp11.h b/gcc/config/pdp11/pdp11.h
index a1a96a1..2904acd 100644
--- a/gcc/config/pdp11/pdp11.h
+++ b/gcc/config/pdp11/pdp11.h
@@ -468,40 +468,6 @@ extern int current_first_parm_offset;
 #define INIT_CUMULATIVE_ARGS(CUM, FNTYPE, LIBNAME, INDIRECT, N_NAMED_ARGS) \
  ((CUM) = 0)
 
-/* Update the data in CUM to advance over an argument
-   of mode MODE and data type TYPE.
-   (TYPE is null for libcalls where that information may not be available.)  
-
-*/
-
-
-#define FUNCTION_ARG_ADVANCE(CUM, MODE, TYPE, NAMED)	\
- ((CUM) += ((MODE) != BLKmode			\
-	    ? (GET_MODE_SIZE (MODE))		\
-	    : (int_size_in_bytes (TYPE))))	
-
-/* Determine where to put an argument to a function.
-   Value is zero to push the argument on the stack,
-   or a hard register in which to store the argument.
-
-   MODE is the argument's machine mode.
-   TYPE is the data type of the argument (as a tree).
-    This is null for libcalls where that information may
-    not be available.
-   CUM is a variable of type CUMULATIVE_ARGS which gives info about
-    the preceding args and about the function being called.
-   NAMED is nonzero if this argument is a named parameter
-    (otherwise it is an extra parameter matching an ellipsis).  */
-
-#define FUNCTION_ARG(CUM, MODE, TYPE, NAMED)  0
-
-/* Define where a function finds its arguments.
-   This would be different from FUNCTION_ARG if we had register windows.  */
-/*
-#define FUNCTION_INCOMING_ARG(CUM, MODE, TYPE, NAMED)	\
-  FUNCTION_ARG (CUM, MODE, TYPE, NAMED)
-*/
-
 /* Output assembler code to FILE to increment profiler label # LABELNO
    for profiling a function entry.  */
 
