1 /* 2 * Copyright (c) 1997, 2006, 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 // An instanceRefKlass is a specialized instanceKlass for Java 26 // classes that are subclasses of java/lang/ref/Reference. 27 // 28 // These classes are used to implement soft/weak/final/phantom 29 // references and finalization, and need special treatment by the 30 // garbage collector. 31 // 32 // During GC discovered reference objects are added (chained) to one 33 // of the four lists below, depending on the type of reference. 34 // The linked occurs through the next field in class java/lang/ref/Reference. 35 // 36 // Afterwards, the discovered references are processed in decreasing 37 // order of reachability. Reference objects eligible for notification 38 // are linked to the static pending_list in class java/lang/ref/Reference, 39 // and the pending list lock object in the same class is notified. 40 41 42 class instanceRefKlass: public instanceKlass { 43 public: 44 // Type testing 45 bool oop_is_instanceRef() const { return true; } 46 47 // Casting from klassOop 48 static instanceRefKlass* cast(klassOop k) { 49 assert(k->klass_part()->oop_is_instanceRef(), "cast to instanceRefKlass"); 50 return (instanceRefKlass*) k->klass_part(); 51 } 52 53 // allocation 54 DEFINE_ALLOCATE_PERMANENT(instanceRefKlass); 55 56 // Garbage collection 57 int oop_adjust_pointers(oop obj); 58 void oop_follow_contents(oop obj); 59 60 // Parallel Scavenge and Parallel Old 61 PARALLEL_GC_DECLS 62 63 int oop_oop_iterate(oop obj, OopClosure* blk) { 64 return oop_oop_iterate_v(obj, blk); 65 } 66 int oop_oop_iterate_m(oop obj, OopClosure* blk, MemRegion mr) { 67 return oop_oop_iterate_v_m(obj, blk, mr); 68 } 69 70 #define InstanceRefKlass_OOP_OOP_ITERATE_DECL(OopClosureType, nv_suffix) \ 71 int oop_oop_iterate##nv_suffix(oop obj, OopClosureType* blk); \ 72 int oop_oop_iterate##nv_suffix##_m(oop obj, OopClosureType* blk, MemRegion mr); 73 74 ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceRefKlass_OOP_OOP_ITERATE_DECL) 75 ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceRefKlass_OOP_OOP_ITERATE_DECL) 76 77 #ifndef SERIALGC 78 #define InstanceRefKlass_OOP_OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \ 79 int oop_oop_iterate_backwards##nv_suffix(oop obj, OopClosureType* blk); 80 81 ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceRefKlass_OOP_OOP_ITERATE_BACKWARDS_DECL) 82 ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceRefKlass_OOP_OOP_ITERATE_BACKWARDS_DECL) 83 #endif // !SERIALGC 84 85 static void release_and_notify_pending_list_lock(BasicLock *pending_list_basic_lock); 86 static void acquire_pending_list_lock(BasicLock *pending_list_basic_lock); 87 88 // Update non-static oop maps so 'referent', 'nextPending' and 89 // 'discovered' will look like non-oops 90 static void update_nonstatic_oop_maps(klassOop k); 91 92 public: 93 // Verification 94 void oop_verify_on(oop obj, outputStream* st); 95 };