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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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12 * version 2 for more details (a copy is included in the LICENSE file that
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24
25#ifndef SHARE_OOPS_INSTANCEMIRRORKLASS_HPP
26#define SHARE_OOPS_INSTANCEMIRRORKLASS_HPP
27
28#include "classfile/systemDictionary.hpp"
29#include "oops/instanceKlass.hpp"
30#include "runtime/handles.hpp"
31#include "utilities/macros.hpp"
32
33class ClassFileParser;
34
35// An InstanceMirrorKlass is a specialized InstanceKlass for
36// java.lang.Class instances. These instances are special because
37// they contain the static fields of the class in addition to the
38// normal fields of Class. This means they are variable sized
39// instances and need special logic for computing their size and for
40// iteration of their oops.
41
42
43class InstanceMirrorKlass: public InstanceKlass {
44 friend class VMStructs;
45 friend class InstanceKlass;
46
47 public:
48 static const KlassID ID = InstanceMirrorKlassID;
49
50 private:
51 static int _offset_of_static_fields;
52
53 InstanceMirrorKlass(const ClassFileParser& parser) : InstanceKlass(parser, InstanceKlass::_misc_kind_mirror, ID) {}
54
55 public:
56 InstanceMirrorKlass() { assert(DumpSharedSpaces || UseSharedSpaces, "only for CDS"); }
57
58 // Casting from Klass*
59 static InstanceMirrorKlass* cast(Klass* k) {
60 assert(InstanceKlass::cast(k)->is_mirror_instance_klass(),
61 "cast to InstanceMirrorKlass");
62 return static_cast<InstanceMirrorKlass*>(k);
63 }
64
65 // Returns the size of the instance including the extra static fields.
66 virtual int oop_size(oop obj) const;
67
68 // Static field offset is an offset into the Heap, should be converted by
69 // based on UseCompressedOop for traversal
70 static HeapWord* start_of_static_fields(oop obj) {
71 return (HeapWord*)(cast_from_oop<intptr_t>(obj) + offset_of_static_fields());
72 }
73
74 static void init_offset_of_static_fields() {
75 // Cache the offset of the static fields in the Class instance
76 assert(_offset_of_static_fields == 0, "once");
77 _offset_of_static_fields = InstanceMirrorKlass::cast(SystemDictionary::Class_klass())->size_helper() << LogHeapWordSize;
78 }
79
80 static int offset_of_static_fields() {
81 return _offset_of_static_fields;
82 }
83
84 int compute_static_oop_field_count(oop obj);
85
86 // Given a Klass return the size of the instance
87 int instance_size(Klass* k);
88
89 // allocation
90 instanceOop allocate_instance(Klass* k, TRAPS);
91
92 static void serialize_offsets(class SerializeClosure* f) NOT_CDS_RETURN;
93
94 // Oop fields (and metadata) iterators
95 //
96 // The InstanceMirrorKlass iterators also visit the hidden Klass pointer.
97
98 // Iterate over the static fields.
99 template <typename T, class OopClosureType>
100 inline void oop_oop_iterate_statics(oop obj, OopClosureType* closure);
101
102 // Forward iteration
103 // Iterate over the oop fields and metadata.
104 template <typename T, class OopClosureType>
105 inline void oop_oop_iterate(oop obj, OopClosureType* closure);
106
107 // Reverse iteration
108 // Iterate over the oop fields and metadata.
109 template <typename T, class OopClosureType>
110 inline void oop_oop_iterate_reverse(oop obj, OopClosureType* closure);
111
112 // Bounded range iteration
113 // Iterate over the oop fields and metadata.
114 template <typename T, class OopClosureType>
115 inline void oop_oop_iterate_bounded(oop obj, OopClosureType* closure, MemRegion mr);
116
117 private:
118
119 // Iterate over the static fields.
120 template <typename T, class OopClosureType>
121 inline void oop_oop_iterate_statics_bounded(oop obj, OopClosureType* closure, MemRegion mr);
122};
123
124#endif // SHARE_OOPS_INSTANCEMIRRORKLASS_HPP
125