--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/agent/src/share/classes/sun/jvm/hotspot/runtime/JavaCallWrapper.java	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,75 @@
+/*
+ * Copyright 2000-2005 Sun Microsystems, Inc.  All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+package sun.jvm.hotspot.runtime;
+
+import java.util.*;
+import sun.jvm.hotspot.debugger.*;
+import sun.jvm.hotspot.types.*;
+
+/** <P> A JavaCallWrapper is constructed before each JavaCall and
+    destroyed after the call.  Its purpose is to allocate/deallocate a
+    new handle block and to save/restore the last Java fp/sp. A
+    pointer to the JavaCallWrapper is stored on the stack. </P>
+
+    <P> NOTE: this port is very minimal and is only designed to get
+    frame traversal working. FIXME: we will have to add platform-
+    specific stuff later and therefore a factory for these
+    objects. </P> */
+
+public class JavaCallWrapper extends VMObject {
+  protected static AddressField  anchorField;
+  private static AddressField  lastJavaSPField;
+  private static AddressField  lastJavaPCField;
+
+  static {
+    VM.registerVMInitializedObserver(new Observer() {
+        public void update(Observable o, Object data) {
+          initialize(VM.getVM().getTypeDataBase());
+        }
+      });
+  }
+
+  private static synchronized void initialize(TypeDataBase db) {
+    Type type = db.lookupType("JavaCallWrapper");
+    Type anchorType = db.lookupType("JavaFrameAnchor");
+
+    anchorField      = type.getAddressField("_anchor");
+    lastJavaSPField  = anchorType.getAddressField("_last_Java_sp");
+    lastJavaPCField  = anchorType.getAddressField("_last_Java_pc");
+  }
+
+  public JavaCallWrapper(Address addr) {
+    super(addr);
+  }
+
+  public Address getLastJavaSP() {
+    return lastJavaSPField.getValue(addr.addOffsetTo(anchorField.getOffset()));
+  }
+
+  public Address getLastJavaPC() {
+    return lastJavaPCField.getValue(addr.addOffsetTo(anchorField.getOffset()));
+  }
+
+}