1 /*

     2  * Copyright (c) 2011, 2012, Oracle and/or its affiliates. All rights reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.

     8  *

     9  * This code is distributed in the hope that it will be useful, but WITHOUT

    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    12  * version 2 for more details (a copy is included in the LICENSE file that

    13  * accompanied this code).

    14  *

    15  * You should have received a copy of the GNU General Public License version

    16  * 2 along with this work; if not, write to the Free Software Foundation,

    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    18  *

    19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    20  * or visit www.oracle.com if you need additional information or have any

    21  * questions.

    22  *

    23  */

    24 

    25 #ifndef SHARE_VM_CI_CIBASEOBJECT_HPP

    26 #define SHARE_VM_CI_CIBASEOBJECT_HPP

    27 

    28 #include "ci/ciClassList.hpp"

    29 #include "memory/allocation.hpp"

    30 #include "runtime/handles.hpp"

    31 #include "runtime/jniHandles.hpp"

    32 

    33 // ciBaseObject

    34 //

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

    36 // Its subclasses are structured in a hierarchy which mirrors

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

    38 // oopHierarchy.hpp).  Each instance of ciBaseObject holds a handle

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

    40 // for accessing the information in its oop.  By using the ciBaseObject

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

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

    43 // GC and compilation can proceed independently without

    44 // interference.

    45 //

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

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

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

    49 // reflected in the interface and instead the Klass hierarchy

    50 // is directly modeled as the subclasses of ciKlass.

    51 class ciBaseObject : public ResourceObj {

    52   CI_PACKAGE_ACCESS

    53   friend class ciEnv;

    54 

    55 protected:

    56   uint     _ident;

    57 

    58   enum { FLAG_BITS   = 1 };

    59   enum {

    60          SCAVENGABLE_FLAG = 1

    61        };

    62 protected:

    63   ciBaseObject(): _ident(0) {}

    64 

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

    66 

    67   void set_ident(uint id);

    68 

    69 public:

    70   // A number unique to this object.

    71   uint ident();

    72 

    73   // What kind of ciBaseObject is this?

    74   virtual bool is_symbol() const       { return false; }

    75   virtual bool is_object() const       { return false; }

    76   virtual bool is_metadata() const     { return false; }

    77 

    78   ciSymbol* as_symbol() {

    79     assert(is_symbol(), "must be");

    80     return (ciSymbol*)this;

    81   }

    82   ciObject* as_object() {

    83     assert(is_object(), "must be");

    84     return (ciObject*)this;

    85   }

    86   ciMetadata* as_metadata() {

    87     assert(is_metadata(), "must be");

    88     return (ciMetadata*)this;

    89   }

    90 };

    91 #endif // SHARE_VM_CI_CIBASEOBJECT_HPP