--- a/hotspot/agent/src/share/classes/sun/jvm/hotspot/code/RuntimeStub.java	Sat Sep 03 14:03:54 2011 -0700
+++ b/hotspot/agent/src/share/classes/sun/jvm/hotspot/code/RuntimeStub.java	Mon Sep 05 17:09:05 2011 -0700
@@ -30,6 +30,8 @@
 import sun.jvm.hotspot.types.*;
 
 public class RuntimeStub extends CodeBlob {
+  private static CIntegerField callerMustGCArgumentsField;
+
   static {
     VM.registerVMInitializedObserver(new Observer() {
         public void update(Observable o, Object data) {
@@ -40,6 +42,7 @@
 
   private static void initialize(TypeDataBase db) {
     Type type = db.lookupType("RuntimeStub");
+    callerMustGCArgumentsField                = type.getCIntegerField("_caller_must_gc_arguments");
 
     // FIXME: add any needed fields
   }
@@ -52,6 +55,11 @@
     return true;
   }
 
+  public boolean callerMustGCArguments() {
+    return callerMustGCArgumentsField.getValue(addr) != 0;
+  }
+
+
   public String getName() {
     return "RuntimeStub: " + super.getName();
   }