1 /* 2 * Copyright (c) 1997, 2017, 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_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 32 class 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 51 class 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 77 private: 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 // Apply the closure to all fields. No reference discovery is done. 127 template <bool nv, typename T, class OopClosureType, class Contains> 128 static void oop_oop_iterate_fields(oop obj, OopClosureType* closure, Contains& contains); 129 130 template <typename T> 131 static void trace_reference_gc(const char *s, oop obj, T* referent_addr, T* next_addr, T* discovered_addr) NOT_DEBUG_RETURN; 132 133 public: 134 135 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_OOP_ITERATE_DECL) 136 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_OOP_ITERATE_DECL) 137 138 #if INCLUDE_ALL_GCS 139 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_OOP_ITERATE_DECL_BACKWARDS) 140 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_OOP_ITERATE_DECL_BACKWARDS) 141 #endif // INCLUDE_ALL_GCS 142 143 // Update non-static oop maps so 'referent', 'nextPending' and 144 // 'discovered' will look like non-oops 145 static void update_nonstatic_oop_maps(Klass* k); 146 147 public: 148 // Verification 149 void oop_verify_on(oop obj, outputStream* st); 150 }; 151 152 #endif // SHARE_VM_OOPS_INSTANCEREFKLASS_HPP