/*+
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 * Copyright (c) 1999, 2012, Oracle and/or its affiliates. All rights reserved.+
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.+
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 *+
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 * This code is free software; you can redistribute it and/or modify it+
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 * under the terms of the GNU General Public License version 2 only, as+
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 * published by the Free Software Foundation.+
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 *+
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 * This code is distributed in the hope that it will be useful, but WITHOUT+
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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or+
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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License+
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 * version 2 for more details (a copy is included in the LICENSE file that+
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 * accompanied this code).+
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 *+
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 * You should have received a copy of the GNU General Public License version+
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 * 2 along with this work; if not, write to the Free Software Foundation,+
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 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.+
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 *+
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 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA+
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 * or visit www.oracle.com if you need additional information or have any+
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 * questions.+
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 *+
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 */+
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+
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#ifndef SHARE_VM_CI_CIOBJECT_HPP+
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#define SHARE_VM_CI_CIOBJECT_HPP+
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+
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#include "ci/ciBaseObject.hpp"+
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#include "ci/ciClassList.hpp"+
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#include "memory/allocation.hpp"+
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#include "runtime/handles.hpp"+
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#include "runtime/jniHandles.hpp"+
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+
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// ciObject+
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//+
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// This class represents an oop in the HotSpot virtual machine.+
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// Its subclasses are structured in a hierarchy which mirrors+
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// an aggregate of the VM's oop and klass hierarchies (see+
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// oopHierarchy.hpp).  Each instance of ciObject holds a handle+
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// to a corresponding oop on the VM side and provides routines+
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// for accessing the information in its oop.  By using the ciObject+
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// hierarchy for accessing oops in the VM, the compiler ensures+
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// that it is safe with respect to garbage collection; that is,+
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// GC and compilation can proceed independently without+
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// interference.+
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//+
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// Within the VM, the oop and klass hierarchies are separate.+
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// The compiler interface does not preserve this separation --+
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// the distinction between `Klass*' and `Klass' are not+
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// reflected in the interface and instead the Klass hierarchy+
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// is directly modeled as the subclasses of ciKlass.+
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class ciObject : public ciBaseObject {+
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  CI_PACKAGE_ACCESS+
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  friend class ciEnv;+
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+
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private:+
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  // A JNI handle referring to an oop in the VM.  This+
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  // handle may, in a small set of cases, correctly be NULL.+
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  jobject  _handle;+
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  ciKlass* _klass;+
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+
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protected:+
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  ciObject();+
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  ciObject(oop o);+
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  ciObject(Handle h);+
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  ciObject(ciKlass* klass);+
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+
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  jobject      handle()  const { return _handle; }+
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  // Get the VM oop that this object holds.+
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  oop get_oop() const {+
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    assert(_handle != NULL, "null oop");+
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    return JNIHandles::resolve_non_null(_handle);+
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  }+
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+
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  void init_flags_from(oop x);+
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+
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  // Virtual behavior of the print() method.+
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  virtual void print_impl(outputStream* st) {}+
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+
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  virtual const char* type_string() { return "ciObject"; }+
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+
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public:+
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  // The klass of this ciObject.+
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  ciKlass* klass();+
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+
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  // Are two ciObjects equal?+
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  bool equals(ciObject* obj);+
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+
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  // A hash value for the convenience of compilers.+
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  int hash();+
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+
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  // Tells if this oop has an encoding as a constant.+
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  // True if is_perm is true.+
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  // Also true if ScavengeRootsInCode is non-zero.+
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  // If it does not have an encoding, the compiler is responsible for+
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  // making other arrangements for dealing with the oop.+
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  // See ciEnv::make_array+
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  bool can_be_constant();+
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+
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  // Tells if this oop should be made a constant.+
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  // True if is_perm is true or ScavengeRootsInCode > 1.+
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  bool should_be_constant();+
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+
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  // Might this object possibly move during a scavenge operation?+
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  // If the answer is true and ScavengeRootsInCode==0, the oop cannot be embedded in code.+
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  bool is_scavengable() { return (_ident & SCAVENGABLE_FLAG) != 0; }+
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+
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  // The address which the compiler should embed into the+
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  // generated code to represent this oop.  This address+
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  // is not the true address of the oop -- it will get patched+
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  // during nmethod creation.+
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  //+
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  // Usage note: no address arithmetic allowed.  Oop must+
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  // be registered with the oopRecorder.+
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  jobject constant_encoding();+
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+
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  virtual bool is_object() const            { return true; }+
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+
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  // What kind of ciObject is this?+
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  virtual bool is_null_object()       const { return false; }+
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  virtual bool is_call_site()         const { return false; }+
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  virtual bool is_cpcache()           const { return false; }+
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  virtual bool is_instance()                { return false; }+
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  virtual bool is_member_name()       const { return false; }+
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  virtual bool is_method_handle()     const { return false; }+
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  virtual bool is_method_type()       const { return false; }+
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  virtual bool is_array()                   { return false; }+
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  virtual bool is_obj_array()               { return false; }+
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  virtual bool is_type_array()              { return false; }+
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+
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  // Is this a type or value which has no associated class?+
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  // It is true of primitive types and null objects.+
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  virtual bool is_classless() const         { return false; }+
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+
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  // Note: some ciObjects refer to oops which have yet to be created.+
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  // We refer to these as "unloaded".  Specifically, there are+
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  // unloaded instances of java.lang.Class,+
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  // java.lang.invoke.MethodHandle, and java.lang.invoke.MethodType.+
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  // By convention the ciNullObject is considered loaded, and+
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  // primitive types are considered loaded.+
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  bool is_loaded() const {+
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    return handle() != NULL || is_classless();+
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  }+
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+
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  // Subclass casting with assertions.+
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  ciNullObject* as_null_object() {+
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    assert(is_null_object(), "bad cast");+
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    return (ciNullObject*)this;+
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  }+
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  ciCallSite* as_call_site() {+
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    assert(is_call_site(), "bad cast");+
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    return (ciCallSite*)this;+
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  }+
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  ciInstance* as_instance() {+
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    assert(is_instance(), "bad cast");+
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    return (ciInstance*)this;+
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  }+
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  ciMemberName* as_member_name() {+
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    assert(is_member_name(), "bad cast");+
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    return (ciMemberName*)this;+
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  }+
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  ciMethodHandle* as_method_handle() {+
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    assert(is_method_handle(), "bad cast");+
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    return (ciMethodHandle*)this;+
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  }+
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  ciMethodType* as_method_type() {+
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    assert(is_method_type(), "bad cast");+
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    return (ciMethodType*)this;+
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  }+
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  ciArray* as_array() {+
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    assert(is_array(), "bad cast");+
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    return (ciArray*)this;+
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  }+
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  ciObjArray* as_obj_array() {+
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    assert(is_obj_array(), "bad cast");+
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    return (ciObjArray*)this;+
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  }+
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  ciTypeArray* as_type_array() {+
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    assert(is_type_array(), "bad cast");+
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    return (ciTypeArray*)this;+
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  }+
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+
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  // Print debugging output about this ciObject.+
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  void print(outputStream* st);+
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  void print() { print(tty); }  // GDB cannot handle default arguments+
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+
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  // Print debugging output about the oop this ciObject represents.+
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  void print_oop(outputStream* st = tty);+
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};+
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+
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#endif // SHARE_VM_CI_CIOBJECT_HPP+
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