1 /* 2 * Copyright (c) 2011, 2013, 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 "oops/instanceKlass.hpp" 30 #include "runtime/handles.hpp" 31 #include "utilities/macros.hpp" 32 33 // An InstanceMirrorKlass is a specialized InstanceKlass for 34 // java.lang.Class instances. These instances are special because 35 // they contain the static fields of the class in addition to the 36 // normal fields of Class. This means they are variable sized 37 // instances and need special logic for computing their size and for 38 // iteration of their oops. 39 40 41 class InstanceMirrorKlass: public InstanceKlass { 42 friend class VMStructs; 43 friend class InstanceKlass; 44 45 private: 46 static int _offset_of_static_fields; 47 48 // Constructor 49 InstanceMirrorKlass(int vtable_len, int itable_len, int static_field_size, int nonstatic_oop_map_size, ReferenceType rt, AccessFlags access_flags, bool is_anonymous); 50 51 public: 52 InstanceMirrorKlass() { assert(DumpSharedSpaces || UseSharedSpaces, "only for CDS"); } 53 // Type testing 54 bool oop_is_instanceMirror() const { return true; } 55 56 // Casting from Klass* 57 static InstanceMirrorKlass* cast(Klass* k) { 58 assert(k->oop_is_instanceMirror(), "cast to InstanceMirrorKlass"); 59 return (InstanceMirrorKlass*) k; 60 } 61 62 // Returns the size of the instance including the extra static fields. 63 virtual int oop_size(oop obj) const; 64 65 // Static field offset is an offset into the Heap, should be converted by 66 // based on UseCompressedOop for traversal 67 static HeapWord* start_of_static_fields(oop obj) { 68 return (HeapWord*)(cast_from_oop<intptr_t>(obj) + offset_of_static_fields()); 69 } 70 71 static void init_offset_of_static_fields() { 72 // Cache the offset of the static fields in the Class instance 73 assert(_offset_of_static_fields == 0, "once"); 74 _offset_of_static_fields = InstanceMirrorKlass::cast(SystemDictionary::Class_klass())->size_helper() << LogHeapWordSize; 75 } 76 77 static int offset_of_static_fields() { 78 return _offset_of_static_fields; 79 } 80 81 int compute_static_oop_field_count(oop obj); 82 83 // Given a Klass return the size of the instance 84 int instance_size(KlassHandle k); 85 86 // allocation 87 instanceOop allocate_instance(KlassHandle k, TRAPS); 88 89 // Garbage collection 90 int oop_adjust_pointers(oop obj); 91 void oop_follow_contents(oop obj); 92 93 // Parallel Scavenge and Parallel Old 94 PARALLEL_GC_DECLS 95 96 template <bool nv, typename OopClosureType> 97 int oop_oop_iterate(oop obj, OopClosureType* blk); 98 99 template <bool nv, typename OopClosureType> 100 int oop_oop_iterate_m(oop obj, OopClosureType* blk, MemRegion mr); 101 102 #if INCLUDE_ALL_GCS 103 template <bool nv, typename OopClosureType> 104 int oop_oop_iterate_backwards(oop obj, OopClosureType* blk); 105 #endif // INCLUDE_ALL_GCS 106 }; 107 108 #endif // SHARE_VM_OOPS_INSTANCEMIRRORKLASS_HPP