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 *

 * 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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#include "ci/ciBaseObject.hpp"

#include "ci/ciClassList.hpp"

#include "runtime/handles.hpp"

#include "runtime/jniHandles.hpp"

// ciObject

//

// This class represents an oop in the HotSpot virtual machine.

// Its subclasses are structured in a hierarchy which mirrors

// an aggregate of the VM's oop and klass hierarchies (see

// oopHierarchy.hpp).  Each instance of ciObject holds a handle

// to a corresponding oop on the VM side and provides routines

// for accessing the information in its oop.  By using the ciObject

// hierarchy for accessing oops in the VM, the compiler ensures

// that it is safe with respect to garbage collection; that is,

// GC and compilation can proceed independently without

// interference.

//

// Within the VM, the oop and klass hierarchies are separate.

// The compiler interface does not preserve this separation --

// the distinction between `Klass*' and `Klass' are not

// reflected in the interface and instead the Klass hierarchy

// is directly modeled as the subclasses of ciKlass.

class ciObject : public ciBaseObject {

  CI_PACKAGE_ACCESS

  friend class ciEnv;

private:

  // A JNI handle referring to an oop in the VM.  This

  // handle may, in a small set of cases, correctly be NULL.

  jobject  _handle;

  ciKlass* _klass;

protected:

  ciObject();

  ciObject(oop o);

  ciObject(Handle h);

  ciObject(ciKlass* klass);

  jobject      handle()  const { return _handle; }

  // Get the VM oop that this object holds.

  oop get_oop() const;

  void init_flags_from(oop x);

  // Virtual behavior of the print() method.

  virtual void print_impl(outputStream* st) {}

  virtual const char* type_string() { return "ciObject"; }

public:

  // The klass of this ciObject.

  ciKlass* klass();

  // Are two ciObjects equal?

  bool equals(ciObject* obj);

  // A hash value for the convenience of compilers.

  int hash();

  // Tells if this oop has an encoding as a constant.

  // True if is_perm is true.

  // Also true if ScavengeRootsInCode is non-zero.

  // If it does not have an encoding, the compiler is responsible for

  // making other arrangements for dealing with the oop.

  // See ciEnv::make_array

  bool can_be_constant();

  // Tells if this oop should be made a constant.

  // True if is_perm is true or ScavengeRootsInCode > 1.

  bool should_be_constant();

  // Might this object possibly move during a scavenge operation?

  // If the answer is true and ScavengeRootsInCode==0, the oop cannot be embedded in code.

  bool is_scavengable() { return (_ident & SCAVENGABLE_FLAG) != 0; }

  // The address which the compiler should embed into the

  // generated code to represent this oop.  This address

  // is not the true address of the oop -- it will get patched

  // during nmethod creation.

  //

  // Usage note: no address arithmetic allowed.  Oop must

  // be registered with the oopRecorder.

  jobject constant_encoding();

  virtual bool is_object() const            { return true; }

  // What kind of ciObject is this?

  virtual bool is_null_object()       const { return false; }

  virtual bool is_call_site()         const { return false; }

  virtual bool is_cpcache()           const { return false; }

  virtual bool is_instance()                { return false; }

  virtual bool is_member_name()       const { return false; }

  virtual bool is_method_handle()     const { return false; }

  virtual bool is_method_type()       const { return false; }

  virtual bool is_array()                   { return false; }

  virtual bool is_obj_array()               { return false; }

  virtual bool is_type_array()              { return false; }

  // Is this a type or value which has no associated class?

  // It is true of primitive types and null objects.

  virtual bool is_classless() const         { return false; }

  virtual void dump_replay_data(outputStream* st) { /* do nothing */ }

  // Note: some ciObjects refer to oops which have yet to be created.

  // We refer to these as "unloaded".  Specifically, there are

  // unloaded instances of java.lang.Class,

  // java.lang.invoke.MethodHandle, and java.lang.invoke.MethodType.

  // By convention the ciNullObject is considered loaded, and

  // primitive types are considered loaded.

  bool is_loaded() const {

    return handle() != NULL || is_classless();

  }

  // Subclass casting with assertions.

  ciNullObject* as_null_object() {

    assert(is_null_object(), "bad cast");

    return (ciNullObject*)this;

  }

  ciCallSite* as_call_site() {

    assert(is_call_site(), "bad cast");

    return (ciCallSite*)this;

  }

  ciInstance* as_instance() {

    assert(is_instance(), "bad cast");

    return (ciInstance*)this;

  }

  ciMemberName* as_member_name() {

    assert(is_member_name(), "bad cast");

    return (ciMemberName*)this;

  }

  ciMethodHandle* as_method_handle() {

    assert(is_method_handle(), "bad cast");

    return (ciMethodHandle*)this;

  }

  ciMethodType* as_method_type() {

    assert(is_method_type(), "bad cast");

    return (ciMethodType*)this;

  }

  ciArray* as_array() {

    assert(is_array(), "bad cast");

    return (ciArray*)this;

  }

  ciObjArray* as_obj_array() {

    assert(is_obj_array(), "bad cast");

    return (ciObjArray*)this;

  }

  ciTypeArray* as_type_array() {

    assert(is_type_array(), "bad cast");

    return (ciTypeArray*)this;

  }

  // Print debugging output about this ciObject.

  void print(outputStream* st);

  void print() { print(tty); }  // GDB cannot handle default arguments

  // Print debugging output about the oop this ciObject represents.

  void print_oop(outputStream* st = tty);

};