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24
25#ifndef SHARE_VM_OOPS_INSTANCEREFKLASS_HPP
26#define SHARE_VM_OOPS_INSTANCEREFKLASS_HPP
27
28#include "gc/shared/specialized_oop_closures.hpp"
29#include "oops/instanceKlass.hpp"
30#include "utilities/macros.hpp"
31
32class ClassFileParser;
33
34// An InstanceRefKlass is a specialized InstanceKlass for Java
35// classes that are subclasses of java/lang/ref/Reference.
36//
37// These classes are used to implement soft/weak/final/phantom
38// references and finalization, and need special treatment by the
39// garbage collector.
40//
41// During GC discovered reference objects are added (chained) to one
42// of the four lists below, depending on the type of reference.
43// The linked occurs through the next field in class java/lang/ref/Reference.
44//
45// Afterwards, the discovered references are processed in decreasing
46// order of reachability. Reference objects eligible for notification
47// are linked to the static pending_list in class java/lang/ref/Reference,
48// and the pending list lock object in the same class is notified.
49
50
51class InstanceRefKlass: public InstanceKlass {
52  friend class InstanceKlass;
53 private:
54  InstanceRefKlass(const ClassFileParser& parser) : InstanceKlass(parser, InstanceKlass::_misc_kind_reference) {}
55
56 public:
57  InstanceRefKlass() { assert(DumpSharedSpaces || UseSharedSpaces, "only for CDS"); }
58
59  // GC specific object visitors
60  //
61#if INCLUDE_ALL_GCS
62  // Parallel Scavenge
63  void oop_ps_push_contents(  oop obj, PSPromotionManager* pm);
64  // Parallel Compact
65  void oop_pc_follow_contents(oop obj, ParCompactionManager* cm);
66  void oop_pc_update_pointers(oop obj, ParCompactionManager* cm);
67#endif
68
69  // Oop fields (and metadata) iterators
70  //  [nv = true]  Use non-virtual calls to do_oop_nv.
71  //  [nv = false] Use virtual calls to do_oop.
72  //
73  // The InstanceRefKlass iterators also support reference processing.
74
75
76  // Forward iteration
77private:
78  // Iterate over all oop fields and metadata.
79  template <bool nv, class OopClosureType>
80  inline void oop_oop_iterate(oop obj, OopClosureType* closure);
81
82  // Reverse iteration
83#if INCLUDE_ALL_GCS
84  // Iterate over all oop fields and metadata.
85  template <bool nv, class OopClosureType>
86  inline void oop_oop_iterate_reverse(oop obj, OopClosureType* closure);
87#endif // INCLUDE_ALL_GCS
88
89  // Bounded range iteration
90  // Iterate over all oop fields and metadata.
91  template <bool nv, class OopClosureType>
92  inline void oop_oop_iterate_bounded(oop obj, OopClosureType* closure, MemRegion mr);
93
94  // Reference processing part of the iterators.
95
96  // Specialized for [T = oop] or [T = narrowOop].
97  template <bool nv, typename T, class OopClosureType, class Contains>
98  inline void oop_oop_iterate_ref_processing_specialized(oop obj, OopClosureType* closure, Contains& contains);
99
100  // Only perform reference processing if the referent object is within mr.
101  template <bool nv, class OopClosureType>
102  inline void oop_oop_iterate_ref_processing_bounded(oop obj, OopClosureType* closure, MemRegion mr);
103
104  // Reference processing
105  template <bool nv, class OopClosureType>
106  inline void oop_oop_iterate_ref_processing(oop obj, OopClosureType* closure);
107
108  // Building blocks for specialized handling.
109  template <bool nv, typename T, class OopClosureType, class Contains>
110  static void do_referent(oop obj, OopClosureType* closure, Contains& contains);
111
112  template <bool nv, typename T, class OopClosureType, class Contains>
113  static void do_next(oop obj, OopClosureType* closure, Contains& contains);
114
115  template <bool nv, typename T, class OopClosureType, class Contains>
116  static void do_discovered(oop obj, OopClosureType* closure, Contains& contains);
117
118  template <typename T, class OopClosureType>
119  static bool try_discover(oop obj, ReferenceType type, OopClosureType* closure);
120
121  // Do discovery while handling InstanceRefKlasses. Reference discovery
122  // is only done if the closure provides a ReferenceProcessor.
123  template <bool nv, typename T, class OopClosureType, class Contains>
124  static void oop_oop_iterate_discovery(oop obj, ReferenceType type, OopClosureType* closure, Contains& contains);
125
126  // Used for a special case in G1 where the closure needs to be applied
127  // to the discovered field. Reference discovery is also done if the
128  // closure provides a ReferenceProcessor.
129  template <bool nv, typename T, class OopClosureType, class Contains>
130  static void oop_oop_iterate_discovered_and_discovery(oop obj, ReferenceType type, OopClosureType* closure, Contains& contains);
131
132  // Apply the closure to all fields. No reference discovery is done.
133  template <bool nv, typename T, class OopClosureType, class Contains>
134  static void oop_oop_iterate_fields(oop obj, OopClosureType* closure, Contains& contains);
135
136  template <typename T>
137  static void trace_reference_gc(const char *s, oop obj) NOT_DEBUG_RETURN;
138
139 public:
140
141  ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_OOP_ITERATE_DECL)
142  ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_OOP_ITERATE_DECL)
143
144#if INCLUDE_ALL_GCS
145  ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_OOP_ITERATE_DECL_BACKWARDS)
146  ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_OOP_ITERATE_DECL_BACKWARDS)
147#endif // INCLUDE_ALL_GCS
148
149  // Update non-static oop maps so 'referent', 'nextPending' and
150  // 'discovered' will look like non-oops
151  static void update_nonstatic_oop_maps(Klass* k);
152
153 public:
154  // Verification
155  void oop_verify_on(oop obj, outputStream* st);
156};
157
158#endif // SHARE_VM_OOPS_INSTANCEREFKLASS_HPP
159