--- a/hotspot/src/share/vm/classfile/javaClasses.cpp	Fri May 06 12:12:29 2011 -0700
+++ b/hotspot/src/share/vm/classfile/javaClasses.cpp	Fri May 06 16:33:13 2011 -0700
@@ -2602,6 +2602,7 @@
 // Support for java_lang_invoke_MethodTypeForm
 
 int java_lang_invoke_MethodTypeForm::_vmslots_offset;
+int java_lang_invoke_MethodTypeForm::_vmlayout_offset;
 int java_lang_invoke_MethodTypeForm::_erasedType_offset;
 int java_lang_invoke_MethodTypeForm::_genericInvoker_offset;
 
@@ -2609,6 +2610,7 @@
   klassOop k = SystemDictionary::MethodTypeForm_klass();
   if (k != NULL) {
     compute_optional_offset(_vmslots_offset,    k, vmSymbols::vmslots_name(),    vmSymbols::int_signature(), true);
+    compute_optional_offset(_vmlayout_offset,   k, vmSymbols::vmlayout_name(),   vmSymbols::object_signature());
     compute_optional_offset(_erasedType_offset, k, vmSymbols::erasedType_name(), vmSymbols::java_lang_invoke_MethodType_signature(), true);
     compute_optional_offset(_genericInvoker_offset, k, vmSymbols::genericInvoker_name(), vmSymbols::java_lang_invoke_MethodHandle_signature(), true);
     if (_genericInvoker_offset == 0)  _genericInvoker_offset = -1;  // set to explicit "empty" value
@@ -2617,9 +2619,31 @@
 
 int java_lang_invoke_MethodTypeForm::vmslots(oop mtform) {
   assert(mtform->klass() == SystemDictionary::MethodTypeForm_klass(), "MTForm only");
+  assert(_vmslots_offset > 0, "");
   return mtform->int_field(_vmslots_offset);
 }
 
+oop java_lang_invoke_MethodTypeForm::vmlayout(oop mtform) {
+  assert(mtform->klass() == SystemDictionary::MethodTypeForm_klass(), "MTForm only");
+  assert(_vmlayout_offset > 0, "");
+  return mtform->obj_field(_vmlayout_offset);
+}
+
+oop java_lang_invoke_MethodTypeForm::init_vmlayout(oop mtform, oop cookie) {
+  assert(mtform->klass() == SystemDictionary::MethodTypeForm_klass(), "MTForm only");
+  oop previous = vmlayout(mtform);
+  if (previous != NULL) {
+    return previous;  // someone else beat us to it
+  }
+  HeapWord* cookie_addr = (HeapWord*) mtform->obj_field_addr<oop>(_vmlayout_offset);
+  OrderAccess::storestore();  // make sure our copy is fully committed
+  previous = oopDesc::atomic_compare_exchange_oop(cookie, cookie_addr, previous);
+  if (previous != NULL) {
+    return previous;  // someone else beat us to it
+  }
+  return cookie;
+}
+
 oop java_lang_invoke_MethodTypeForm::erasedType(oop mtform) {
   assert(mtform->klass() == SystemDictionary::MethodTypeForm_klass(), "MTForm only");
   return mtform->obj_field(_erasedType_offset);