1 /* 2 * Copyright (c) 1997, 2018, 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_OOP_HPP 26 #define SHARE_VM_OOPS_OOP_HPP 27 28 #include "memory/iterator.hpp" 29 #include "memory/memRegion.hpp" 30 #include "oops/access.hpp" 31 #include "oops/metadata.hpp" 32 #include "runtime/atomic.hpp" 33 #include "utilities/macros.hpp" 34 35 // oopDesc is the top baseclass for objects classes. The {name}Desc classes describe 36 // the format of Java objects so the fields can be accessed from C++. 37 // oopDesc is abstract. 38 // (see oopHierarchy for complete oop class hierarchy) 39 // 40 // no virtual functions allowed 41 42 extern bool always_do_update_barrier; 43 44 // Forward declarations. 45 class OopClosure; 46 class ScanClosure; 47 class FastScanClosure; 48 class FilteringClosure; 49 class BarrierSet; 50 class CMSIsAliveClosure; 51 52 class PSPromotionManager; 53 class ParCompactionManager; 54 55 class oopDesc { 56 friend class VMStructs; 57 friend class JVMCIVMStructs; 58 private: 59 volatile markOop _mark; 60 union _metadata { 61 Klass* _klass; 62 narrowKlass _compressed_klass; 63 } _metadata; 64 65 public: 66 inline markOop mark() const; 67 inline markOop mark_raw() const; 68 inline markOop* mark_addr_raw() const; 69 70 inline void set_mark(volatile markOop m); 71 inline void set_mark_raw(volatile markOop m); 72 static inline void set_mark_raw(HeapWord* mem, markOop m); 73 74 inline void release_set_mark(markOop m); 75 inline markOop cas_set_mark(markOop new_mark, markOop old_mark); 76 inline markOop cas_set_mark_raw(markOop new_mark, markOop old_mark, atomic_memory_order order = memory_order_conservative); 77 78 // Used only to re-initialize the mark word (e.g., of promoted 79 // objects during a GC) -- requires a valid klass pointer 80 inline void init_mark(); 81 inline void init_mark_raw(); 82 83 inline Klass* klass() const; 84 inline Klass* klass_or_null() const volatile; 85 inline Klass* klass_or_null_acquire() const volatile; 86 static inline Klass** klass_addr(HeapWord* mem); 87 static inline narrowKlass* compressed_klass_addr(HeapWord* mem); 88 inline Klass** klass_addr(); 89 inline narrowKlass* compressed_klass_addr(); 90 91 inline void set_klass(Klass* k); 92 static inline void release_set_klass(HeapWord* mem, Klass* klass); 93 94 // For klass field compression 95 inline int klass_gap() const; 96 inline void set_klass_gap(int z); 97 static inline void set_klass_gap(HeapWord* mem, int z); 98 // For when the klass pointer is being used as a linked list "next" field. 99 inline void set_klass_to_list_ptr(oop k); 100 inline oop list_ptr_from_klass(); 101 102 // size of object header, aligned to platform wordSize 103 static int header_size() { return sizeof(oopDesc)/HeapWordSize; } 104 105 // Returns whether this is an instance of k or an instance of a subclass of k 106 inline bool is_a(Klass* k) const; 107 108 // Returns the actual oop size of the object 109 inline int size(); 110 111 // Sometimes (for complicated concurrency-related reasons), it is useful 112 // to be able to figure out the size of an object knowing its klass. 113 inline int size_given_klass(Klass* klass); 114 115 // type test operations (inlined in oop.inline.hpp) 116 inline bool is_instance() const; 117 inline bool is_array() const; 118 inline bool is_objArray() const; 119 inline bool is_typeArray() const; 120 121 // type test operations that don't require inclusion of oop.inline.hpp. 122 bool is_instance_noinline() const; 123 bool is_array_noinline() const; 124 bool is_objArray_noinline() const; 125 bool is_typeArray_noinline() const; 126 127 protected: 128 inline oop as_oop() const { return const_cast<oopDesc*>(this); } 129 130 public: 131 // field addresses in oop 132 inline void* field_addr(int offset) const; 133 inline void* field_addr_raw(int offset) const; 134 135 // Need this as public for garbage collection. 136 template <class T> inline T* obj_field_addr_raw(int offset) const; 137 138 template <typename T> inline size_t field_offset(T* p) const; 139 140 // Standard compare function returns negative value if o1 < o2 141 // 0 if o1 == o2 142 // positive value if o1 > o2 143 inline static int compare(oop o1, oop o2) { 144 void* o1_addr = (void*)o1; 145 void* o2_addr = (void*)o2; 146 if (o1_addr < o2_addr) { 147 return -1; 148 } else if (o1_addr > o2_addr) { 149 return 1; 150 } else { 151 return 0; 152 } 153 } 154 155 inline static bool equals(oop o1, oop o2) { return Access<>::equals(o1, o2); } 156 157 inline static bool equals_raw(oop o1, oop o2) { return RawAccess<>::equals(o1, o2); } 158 159 // Access to fields in a instanceOop through these methods. 160 template <DecoratorSet decorator> 161 oop obj_field_access(int offset) const; 162 oop obj_field(int offset) const; 163 void obj_field_put(int offset, oop value); 164 void obj_field_put_raw(int offset, oop value); 165 void obj_field_put_volatile(int offset, oop value); 166 167 Metadata* metadata_field(int offset) const; 168 Metadata* metadata_field_raw(int offset) const; 169 void metadata_field_put(int offset, Metadata* value); 170 171 Metadata* metadata_field_acquire(int offset) const; 172 void release_metadata_field_put(int offset, Metadata* value); 173 174 jbyte byte_field(int offset) const; 175 void byte_field_put(int offset, jbyte contents); 176 177 jchar char_field(int offset) const; 178 void char_field_put(int offset, jchar contents); 179 180 jboolean bool_field(int offset) const; 181 void bool_field_put(int offset, jboolean contents); 182 183 jint int_field(int offset) const; 184 jint int_field_raw(int offset) const; 185 void int_field_put(int offset, jint contents); 186 187 jshort short_field(int offset) const; 188 void short_field_put(int offset, jshort contents); 189 190 jlong long_field(int offset) const; 191 void long_field_put(int offset, jlong contents); 192 193 jfloat float_field(int offset) const; 194 void float_field_put(int offset, jfloat contents); 195 196 jdouble double_field(int offset) const; 197 void double_field_put(int offset, jdouble contents); 198 199 address address_field(int offset) const; 200 void address_field_put(int offset, address contents); 201 202 oop obj_field_acquire(int offset) const; 203 void release_obj_field_put(int offset, oop value); 204 205 jbyte byte_field_acquire(int offset) const; 206 void release_byte_field_put(int offset, jbyte contents); 207 208 jchar char_field_acquire(int offset) const; 209 void release_char_field_put(int offset, jchar contents); 210 211 jboolean bool_field_acquire(int offset) const; 212 void release_bool_field_put(int offset, jboolean contents); 213 214 jint int_field_acquire(int offset) const; 215 void release_int_field_put(int offset, jint contents); 216 217 jshort short_field_acquire(int offset) const; 218 void release_short_field_put(int offset, jshort contents); 219 220 jlong long_field_acquire(int offset) const; 221 void release_long_field_put(int offset, jlong contents); 222 223 jfloat float_field_acquire(int offset) const; 224 void release_float_field_put(int offset, jfloat contents); 225 226 jdouble double_field_acquire(int offset) const; 227 void release_double_field_put(int offset, jdouble contents); 228 229 address address_field_acquire(int offset) const; 230 void release_address_field_put(int offset, address contents); 231 232 // printing functions for VM debugging 233 void print_on(outputStream* st) const; // First level print 234 void print_value_on(outputStream* st) const; // Second level print. 235 void print_address_on(outputStream* st) const; // Address printing 236 237 // printing on default output stream 238 void print(); 239 void print_value(); 240 void print_address(); 241 242 // return the print strings 243 char* print_string(); 244 char* print_value_string(); 245 246 // verification operations 247 static void verify_on(outputStream* st, oopDesc* oop_desc); 248 static void verify(oopDesc* oopDesc); 249 250 // locking operations 251 inline bool is_locked() const; 252 inline bool is_unlocked() const; 253 inline bool has_bias_pattern() const; 254 inline bool has_bias_pattern_raw() const; 255 256 // asserts and guarantees 257 static bool is_oop(oop obj, bool ignore_mark_word = false); 258 static bool is_oop_or_null(oop obj, bool ignore_mark_word = false); 259 #ifndef PRODUCT 260 inline bool is_unlocked_oop() const; 261 static bool is_archive_object(oop p) NOT_CDS_JAVA_HEAP_RETURN_(false); 262 #endif 263 264 // garbage collection 265 inline bool is_gc_marked() const; 266 267 // Forward pointer operations for scavenge 268 inline bool is_forwarded() const; 269 270 inline void forward_to(oop p); 271 inline bool cas_forward_to(oop p, markOop compare, atomic_memory_order order = memory_order_conservative); 272 273 // Like "forward_to", but inserts the forwarding pointer atomically. 274 // Exactly one thread succeeds in inserting the forwarding pointer, and 275 // this call returns "NULL" for that thread; any other thread has the 276 // value of the forwarding pointer returned and does not modify "this". 277 inline oop forward_to_atomic(oop p, atomic_memory_order order = memory_order_conservative); 278 279 inline oop forwardee() const; 280 inline oop forwardee_acquire() const; 281 282 // Age of object during scavenge 283 inline uint age() const; 284 inline void incr_age(); 285 286 // mark-sweep support 287 void follow_body(int begin, int end); 288 289 // Garbage Collection support 290 291 #if INCLUDE_PARALLELGC 292 // Parallel Compact 293 inline void pc_follow_contents(ParCompactionManager* cm); 294 inline void pc_update_contents(ParCompactionManager* cm); 295 // Parallel Scavenge 296 inline void ps_push_contents(PSPromotionManager* pm); 297 #endif 298 299 template <typename OopClosureType> 300 inline void oop_iterate(OopClosureType* cl); 301 302 template <typename OopClosureType> 303 inline void oop_iterate(OopClosureType* cl, MemRegion mr); 304 305 template <typename OopClosureType> 306 inline int oop_iterate_size(OopClosureType* cl); 307 308 template <typename OopClosureType> 309 inline int oop_iterate_size(OopClosureType* cl, MemRegion mr); 310 311 template <typename OopClosureType> 312 inline void oop_iterate_backwards(OopClosureType* cl); 313 314 inline static bool is_instanceof_or_null(oop obj, Klass* klass); 315 316 // identity hash; returns the identity hash key (computes it if necessary) 317 // NOTE with the introduction of UseBiasedLocking that identity_hash() might reach a 318 // safepoint if called on a biased object. Calling code must be aware of that. 319 inline intptr_t identity_hash(); 320 intptr_t slow_identity_hash(); 321 322 // Alternate hashing code if string table is rehashed 323 unsigned int new_hash(juint seed); 324 325 // marks are forwarded to stack when object is locked 326 inline bool has_displaced_mark_raw() const; 327 inline markOop displaced_mark_raw() const; 328 inline void set_displaced_mark_raw(markOop m); 329 330 static bool has_klass_gap(); 331 332 // for code generation 333 static int mark_offset_in_bytes() { return offset_of(oopDesc, _mark); } 334 static int klass_offset_in_bytes() { return offset_of(oopDesc, _metadata._klass); } 335 static int klass_gap_offset_in_bytes() { 336 assert(has_klass_gap(), "only applicable to compressed klass pointers"); 337 return klass_offset_in_bytes() + sizeof(narrowKlass); 338 } 339 }; 340 341 #endif // SHARE_VM_OOPS_OOP_HPP