--- a/hotspot/src/share/vm/ci/ciInstanceKlass.cpp	Thu Jul 08 14:29:44 2010 -0700
+++ b/hotspot/src/share/vm/ci/ciInstanceKlass.cpp	Mon Jul 12 10:58:25 2010 -0700
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1999, 2008, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1999, 2010, Oracle and/or its affiliates. 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
@@ -44,9 +44,7 @@
   _flags = ciFlags(access_flags);
   _has_finalizer = access_flags.has_finalizer();
   _has_subklass = ik->subklass() != NULL;
-  _is_initialized = ik->is_initialized();
-  // Next line must follow and use the result of the previous line:
-  _is_linked = _is_initialized || ik->is_linked();
+  _init_state = (instanceKlass::ClassState)ik->get_init_state();
   _nonstatic_field_size = ik->nonstatic_field_size();
   _has_nonstatic_fields = ik->has_nonstatic_fields();
   _nonstatic_fields = NULL; // initialized lazily by compute_nonstatic_fields:
@@ -91,8 +89,7 @@
   : ciKlass(name, ciInstanceKlassKlass::make())
 {
   assert(name->byte_at(0) != '[', "not an instance klass");
-  _is_initialized = false;
-  _is_linked = false;
+  _init_state = (instanceKlass::ClassState)0;
   _nonstatic_field_size = -1;
   _has_nonstatic_fields = false;
   _nonstatic_fields = NULL;
@@ -109,21 +106,10 @@
 
 // ------------------------------------------------------------------
 // ciInstanceKlass::compute_shared_is_initialized
-bool ciInstanceKlass::compute_shared_is_initialized() {
+void ciInstanceKlass::compute_shared_init_state() {
   GUARDED_VM_ENTRY(
     instanceKlass* ik = get_instanceKlass();
-    _is_initialized = ik->is_initialized();
-    return _is_initialized;
-  )
-}
-
-// ------------------------------------------------------------------
-// ciInstanceKlass::compute_shared_is_linked
-bool ciInstanceKlass::compute_shared_is_linked() {
-  GUARDED_VM_ENTRY(
-    instanceKlass* ik = get_instanceKlass();
-    _is_linked = ik->is_linked();
-    return _is_linked;
+    _init_state = (instanceKlass::ClassState)ik->get_init_state();
   )
 }
 

--- a/hotspot/src/share/vm/ci/ciInstanceKlass.hpp	Thu Jul 08 14:29:44 2010 -0700
+++ b/hotspot/src/share/vm/ci/ciInstanceKlass.hpp	Mon Jul 12 10:58:25 2010 -0700
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1999, 2008, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1999, 2010, Oracle and/or its affiliates. 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
@@ -39,9 +39,8 @@
   jobject                _loader;
   jobject                _protection_domain;
 
+  instanceKlass::ClassState _init_state;           // state of class
   bool                   _is_shared;
-  bool                   _is_initialized;
-  bool                   _is_linked;
   bool                   _has_finalizer;
   bool                   _has_subklass;
   bool                   _has_nonstatic_fields;
@@ -87,27 +86,34 @@
 
   bool is_shared() { return _is_shared; }
 
-  bool compute_shared_is_initialized();
-  bool compute_shared_is_linked();
+  void compute_shared_init_state();
   bool compute_shared_has_subklass();
   int  compute_shared_nof_implementors();
   int  compute_nonstatic_fields();
   GrowableArray<ciField*>* compute_nonstatic_fields_impl(GrowableArray<ciField*>* super_fields);
 
+  // Update the init_state for shared klasses
+  void update_if_shared(instanceKlass::ClassState expected) {
+    if (_is_shared && _init_state != expected) {
+      if (is_loaded()) compute_shared_init_state();
+    }
+  }
+
 public:
   // Has this klass been initialized?
   bool                   is_initialized() {
-    if (_is_shared && !_is_initialized) {
-      return is_loaded() && compute_shared_is_initialized();
-    }
-    return _is_initialized;
+    update_if_shared(instanceKlass::fully_initialized);
+    return _init_state == instanceKlass::fully_initialized;
+  }
+  // Is this klass being initialized?
+  bool                   is_being_initialized() {
+    update_if_shared(instanceKlass::being_initialized);
+    return _init_state == instanceKlass::being_initialized;
   }
   // Has this klass been linked?
   bool                   is_linked() {
-    if (_is_shared && !_is_linked) {
-      return is_loaded() && compute_shared_is_linked();
-    }
-    return _is_linked;
+    update_if_shared(instanceKlass::linked);
+    return _init_state >= instanceKlass::linked;
   }
 
   // General klass information.

--- a/hotspot/src/share/vm/opto/doCall.cpp	Thu Jul 08 14:29:44 2010 -0700
+++ b/hotspot/src/share/vm/opto/doCall.cpp	Mon Jul 12 10:58:25 2010 -0700
@@ -343,7 +343,8 @@
   // being initialized.  Uncommon-trap for not-initialized static or
   // v-calls.  Let interface calls happen.
   ciInstanceKlass* holder_klass = dest_method->holder();
-  if (!holder_klass->is_initialized() &&
+  if (!holder_klass->is_being_initialized() &&
+      !holder_klass->is_initialized() &&
       !holder_klass->is_interface()) {
     uncommon_trap(Deoptimization::Reason_uninitialized,
                   Deoptimization::Action_reinterpret,

--- a/hotspot/src/share/vm/opto/parse.hpp	Thu Jul 08 14:29:44 2010 -0700
+++ b/hotspot/src/share/vm/opto/parse.hpp	Mon Jul 12 10:58:25 2010 -0700
@@ -480,6 +480,7 @@
   bool push_constant(ciConstant con, bool require_constant = false);
 
   // implementation of object creation bytecodes
+  void emit_guard_for_new(ciInstanceKlass* klass);
   void do_new();
   void do_newarray(BasicType elemtype);
   void do_anewarray();

--- a/hotspot/src/share/vm/opto/parseHelper.cpp	Thu Jul 08 14:29:44 2010 -0700
+++ b/hotspot/src/share/vm/opto/parseHelper.cpp	Mon Jul 12 10:58:25 2010 -0700
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1998, 2009, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1998, 2010, Oracle and/or its affiliates. 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
@@ -197,6 +197,43 @@
 }
 
 
+void Parse::emit_guard_for_new(ciInstanceKlass* klass) {
+  // Emit guarded new
+  //   if (klass->_init_thread != current_thread ||
+  //       klass->_init_state != being_initialized)
+  //      uncommon_trap
+  Node* cur_thread = _gvn.transform( new (C, 1) ThreadLocalNode() );
+  Node* merge = new (C, 3) RegionNode(3);
+  _gvn.set_type(merge, Type::CONTROL);
+  Node* kls = makecon(TypeKlassPtr::make(klass));
+
+  Node* init_thread_offset = _gvn.MakeConX(instanceKlass::init_thread_offset_in_bytes() + klassOopDesc::klass_part_offset_in_bytes());
+  Node* adr_node = basic_plus_adr(kls, kls, init_thread_offset);
+  Node* init_thread = make_load(NULL, adr_node, TypeRawPtr::BOTTOM, T_ADDRESS);
+  Node *tst   = Bool( CmpP( init_thread, cur_thread), BoolTest::eq);
+  IfNode* iff = create_and_map_if(control(), tst, PROB_ALWAYS, COUNT_UNKNOWN);
+  set_control(IfTrue(iff));
+  merge->set_req(1, IfFalse(iff));
+
+  Node* init_state_offset = _gvn.MakeConX(instanceKlass::init_state_offset_in_bytes() + klassOopDesc::klass_part_offset_in_bytes());
+  adr_node = basic_plus_adr(kls, kls, init_state_offset);
+  Node* init_state = make_load(NULL, adr_node, TypeInt::INT, T_INT);
+  Node* being_init = _gvn.intcon(instanceKlass::being_initialized);
+  tst   = Bool( CmpI( init_state, being_init), BoolTest::eq);
+  iff = create_and_map_if(control(), tst, PROB_ALWAYS, COUNT_UNKNOWN);
+  set_control(IfTrue(iff));
+  merge->set_req(2, IfFalse(iff));
+
+  PreserveJVMState pjvms(this);
+  record_for_igvn(merge);
+  set_control(merge);
+
+  uncommon_trap(Deoptimization::Reason_uninitialized,
+                Deoptimization::Action_reinterpret,
+                klass);
+}
+
+
 //------------------------------do_new-----------------------------------------
 void Parse::do_new() {
   kill_dead_locals();
@@ -206,7 +243,7 @@
   assert(will_link, "_new: typeflow responsibility");
 
   // Should initialize, or throw an InstantiationError?
-  if (!klass->is_initialized() ||
+  if (!klass->is_initialized() && !klass->is_being_initialized() ||
       klass->is_abstract() || klass->is_interface() ||
       klass->name() == ciSymbol::java_lang_Class() ||
       iter().is_unresolved_klass()) {
@@ -215,6 +252,9 @@
                   klass);
     return;
   }
+  if (klass->is_being_initialized()) {
+    emit_guard_for_new(klass);
+  }
 
   Node* kls = makecon(TypeKlassPtr::make(klass));
   Node* obj = new_instance(kls);