1 /* 2 * Copyright (c) 2011, 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_INSTANCEMIRRORKLASS_HPP 26 #define SHARE_VM_OOPS_INSTANCEMIRRORKLASS_HPP 27 28 #include "classfile/systemDictionary.hpp" 29 #include "gc/shared/specialized_oop_closures.hpp" 30 #include "oops/instanceKlass.hpp" 31 #include "runtime/handles.hpp" 32 #include "utilities/macros.hpp" 33 34 class ClassFileParser; 35 36 // An InstanceMirrorKlass is a specialized InstanceKlass for 37 // java.lang.Class instances. These instances are special because 38 // they contain the static fields of the class in addition to the 39 // normal fields of Class. This means they are variable sized 40 // instances and need special logic for computing their size and for 41 // iteration of their oops. 42 43 44 class InstanceMirrorKlass: public InstanceKlass { 45 friend class VMStructs; 46 friend class InstanceKlass; 47 48 private: 49 static int _offset_of_static_fields; 50 51 InstanceMirrorKlass(const ClassFileParser& parser) : InstanceKlass(parser, InstanceKlass::_misc_kind_mirror) {} 52 53 public: 54 InstanceMirrorKlass() { assert(DumpSharedSpaces || UseSharedSpaces, "only for CDS"); } 55 56 // Casting from Klass* 57 static InstanceMirrorKlass* cast(Klass* k) { 58 assert(InstanceKlass::cast(k)->is_mirror_instance_klass(), 59 "cast to InstanceMirrorKlass"); 60 return static_cast<InstanceMirrorKlass*>(k); 61 } 62 63 // Returns the size of the instance including the extra static fields. 64 virtual int oop_size(oop obj) const; 65 66 // Static field offset is an offset into the Heap, should be converted by 67 // based on UseCompressedOop for traversal 68 static HeapWord* start_of_static_fields(oop obj) { 69 return (HeapWord*)(cast_from_oop<intptr_t>(obj) + offset_of_static_fields()); 70 } 71 72 static void init_offset_of_static_fields() { 73 // Cache the offset of the static fields in the Class instance 74 assert(_offset_of_static_fields == 0, "once"); 75 _offset_of_static_fields = InstanceMirrorKlass::cast(SystemDictionary::Class_klass())->size_helper() << LogHeapWordSize; 76 } 77 78 static int offset_of_static_fields() { 79 return _offset_of_static_fields; 80 } 81 82 int compute_static_oop_field_count(oop obj); 83 84 // Given a Klass return the size of the instance 85 int instance_size(Klass* k); 86 87 // allocation 88 instanceOop allocate_instance(Klass* k, TRAPS); 89 90 // GC specific object visitors 91 // 92 #if INCLUDE_ALL_GCS 93 // Parallel Scavenge 94 void oop_ps_push_contents( oop obj, PSPromotionManager* pm); 95 // Parallel Compact 96 void oop_pc_follow_contents(oop obj, ParCompactionManager* cm); 97 void oop_pc_update_pointers(oop obj, ParCompactionManager* cm); 98 #endif 99 100 // Oop fields (and metadata) iterators 101 // [nv = true] Use non-virtual calls to do_oop_nv. 102 // [nv = false] Use virtual calls to do_oop. 103 // 104 // The InstanceMirrorKlass iterators also visit the hidden Klass pointer. 105 106 public: 107 // Iterate over the static fields. 108 template <bool nv, class OopClosureType> 109 inline void oop_oop_iterate_statics(oop obj, OopClosureType* closure); 110 111 private: 112 // Iterate over the static fields. 113 // Specialized for [T = oop] or [T = narrowOop]. 114 template <bool nv, typename T, class OopClosureType> 115 inline void oop_oop_iterate_statics_specialized(oop obj, OopClosureType* closure); 116 117 // Forward iteration 118 // Iterate over the oop fields and metadata. 119 template <bool nv, class OopClosureType> 120 inline void oop_oop_iterate(oop obj, OopClosureType* closure); 121 122 123 // Reverse iteration 124 #if INCLUDE_ALL_GCS 125 // Iterate over the oop fields and metadata. 126 template <bool nv, class OopClosureType> 127 inline void oop_oop_iterate_reverse(oop obj, OopClosureType* closure); 128 #endif 129 130 131 // Bounded range iteration 132 // Iterate over the oop fields and metadata. 133 template <bool nv, class OopClosureType> 134 inline void oop_oop_iterate_bounded(oop obj, OopClosureType* closure, MemRegion mr); 135 136 // Iterate over the static fields. 137 template <bool nv, class OopClosureType> 138 inline void oop_oop_iterate_statics_bounded(oop obj, OopClosureType* closure, MemRegion mr); 139 140 // Iterate over the static fields. 141 // Specialized for [T = oop] or [T = narrowOop]. 142 template <bool nv, typename T, class OopClosureType> 143 inline void oop_oop_iterate_statics_specialized_bounded(oop obj, OopClosureType* closure, MemRegion mr); 144 145 146 public: 147 148 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_OOP_ITERATE_DECL) 149 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_OOP_ITERATE_DECL) 150 151 #if INCLUDE_ALL_GCS 152 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_OOP_ITERATE_DECL_BACKWARDS) 153 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_OOP_ITERATE_DECL_BACKWARDS) 154 #endif // INCLUDE_ALL_GCS 155 }; 156 157 #endif // SHARE_VM_OOPS_INSTANCEMIRRORKLASS_HPP