ciBaseObject.hpp revision 3602:da91efe96a93 
1/*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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7 * published by the Free Software Foundation.
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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
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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.
51class ciBaseObject : public ResourceObj {
52  CI_PACKAGE_ACCESS
53  friend class ciEnv;
54
55protected:
56  uint     _ident;
57
58  enum { FLAG_BITS   = 1 };
59  enum {
60         SCAVENGABLE_FLAG = 1
61       };
62protected:
63  ciBaseObject(): _ident(0) {}
64
65  virtual const char* type_string() { return "ciBaseObject"; }
66
67  void set_ident(uint id);
68
69public:
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
92