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 // Access to fields in a instanceOop through these methods. 158 template <DecoratorSet decorator> 159 oop obj_field_access(int offset) const; 160 oop obj_field(int offset) const; 161 void obj_field_put(int offset, oop value); 162 void obj_field_put_raw(int offset, oop value); 163 void obj_field_put_volatile(int offset, oop value); 164 165 Metadata* metadata_field(int offset) const; 166 void metadata_field_put(int offset, Metadata* value); 167 168 Metadata* metadata_field_acquire(int offset) const; 169 void release_metadata_field_put(int offset, Metadata* value); 170 171 jbyte byte_field(int offset) const; 172 void byte_field_put(int offset, jbyte contents); 173 174 jchar char_field(int offset) const; 175 void char_field_put(int offset, jchar contents); 176 177 jboolean bool_field(int offset) const; 178 void bool_field_put(int offset, jboolean contents); 179 180 jint int_field(int offset) const; 181 void int_field_put(int offset, jint contents); 182 183 jshort short_field(int offset) const; 184 void short_field_put(int offset, jshort contents); 185 186 jlong long_field(int offset) const; 187 void long_field_put(int offset, jlong contents); 188 189 jfloat float_field(int offset) const; 190 void float_field_put(int offset, jfloat contents); 191 192 jdouble double_field(int offset) const; 193 void double_field_put(int offset, jdouble contents); 194 195 address address_field(int offset) const; 196 void address_field_put(int offset, address contents); 197 198 oop obj_field_acquire(int offset) const; 199 void release_obj_field_put(int offset, oop value); 200 201 jbyte byte_field_acquire(int offset) const; 202 void release_byte_field_put(int offset, jbyte contents); 203 204 jchar char_field_acquire(int offset) const; 205 void release_char_field_put(int offset, jchar contents); 206 207 jboolean bool_field_acquire(int offset) const; 208 void release_bool_field_put(int offset, jboolean contents); 209 210 jint int_field_acquire(int offset) const; 211 void release_int_field_put(int offset, jint contents); 212 213 jshort short_field_acquire(int offset) const; 214 void release_short_field_put(int offset, jshort contents); 215 216 jlong long_field_acquire(int offset) const; 217 void release_long_field_put(int offset, jlong contents); 218 219 jfloat float_field_acquire(int offset) const; 220 void release_float_field_put(int offset, jfloat contents); 221 222 jdouble double_field_acquire(int offset) const; 223 void release_double_field_put(int offset, jdouble contents); 224 225 address address_field_acquire(int offset) const; 226 void release_address_field_put(int offset, address contents); 227 228 // printing functions for VM debugging 229 void print_on(outputStream* st) const; // First level print 230 void print_value_on(outputStream* st) const; // Second level print. 231 void print_address_on(outputStream* st) const; // Address printing 232 233 // printing on default output stream 234 void print(); 235 void print_value(); 236 void print_address(); 237 238 // return the print strings 239 char* print_string(); 240 char* print_value_string(); 241 242 // verification operations 243 static void verify_on(outputStream* st, oopDesc* oop_desc); 244 static void verify(oopDesc* oopDesc); 245 246 // locking operations 247 inline bool is_locked() const; 248 inline bool is_unlocked() const; 249 inline bool has_bias_pattern() const; 250 inline bool has_bias_pattern_raw() const; 251 252 // asserts and guarantees 253 static bool is_oop(oop obj, bool ignore_mark_word = false); 254 static bool is_oop_or_null(oop obj, bool ignore_mark_word = false); 255 #ifndef PRODUCT 256 inline bool is_unlocked_oop() const; 257 #endif 258 259 // garbage collection 260 inline bool is_gc_marked() const; 261 262 // Forward pointer operations for scavenge 263 inline bool is_forwarded() const; 264 265 inline void forward_to(oop p); 266 inline bool cas_forward_to(oop p, markOop compare, atomic_memory_order order = memory_order_conservative); 267 268 // Like "forward_to", but inserts the forwarding pointer atomically. 269 // Exactly one thread succeeds in inserting the forwarding pointer, and 270 // this call returns "NULL" for that thread; any other thread has the 271 // value of the forwarding pointer returned and does not modify "this". 272 inline oop forward_to_atomic(oop p, atomic_memory_order order = memory_order_conservative); 273 274 inline oop forwardee() const; 275 inline oop forwardee_acquire() const; 276 277 // Age of object during scavenge 278 inline uint age() const; 279 inline void incr_age(); 280 281 // mark-sweep support 282 void follow_body(int begin, int end); 283 284 // Garbage Collection support 285 286 #if INCLUDE_PARALLELGC 287 // Parallel Compact 288 inline void pc_follow_contents(ParCompactionManager* cm); 289 inline void pc_update_contents(ParCompactionManager* cm); 290 // Parallel Scavenge 291 inline void ps_push_contents(PSPromotionManager* pm); 292 #endif 293 294 template <typename OopClosureType> 295 inline void oop_iterate(OopClosureType* cl); 296 297 template <typename OopClosureType> 298 inline void oop_iterate(OopClosureType* cl, MemRegion mr); 299 300 template <typename OopClosureType> 301 inline int oop_iterate_size(OopClosureType* cl); 302 303 template <typename OopClosureType> 304 inline int oop_iterate_size(OopClosureType* cl, MemRegion mr); 305 306 template <typename OopClosureType> 307 inline void oop_iterate_backwards(OopClosureType* cl); 308 309 inline static bool is_instanceof_or_null(oop obj, Klass* klass); 310 311 // identity hash; returns the identity hash key (computes it if necessary) 312 // NOTE with the introduction of UseBiasedLocking that identity_hash() might reach a 313 // safepoint if called on a biased object. Calling code must be aware of that. 314 inline intptr_t identity_hash(); 315 intptr_t slow_identity_hash(); 316 317 // Alternate hashing code if string table is rehashed 318 unsigned int new_hash(juint seed); 319 320 // marks are forwarded to stack when object is locked 321 inline bool has_displaced_mark_raw() const; 322 inline markOop displaced_mark_raw() const; 323 inline void set_displaced_mark_raw(markOop m); 324 325 static bool has_klass_gap(); 326 327 // for code generation 328 static int mark_offset_in_bytes() { return offset_of(oopDesc, _mark); } 329 static int klass_offset_in_bytes() { return offset_of(oopDesc, _metadata._klass); } 330 static int klass_gap_offset_in_bytes() { 331 assert(has_klass_gap(), "only applicable to compressed klass pointers"); 332 return klass_offset_in_bytes() + sizeof(narrowKlass); 333 } 334 }; 335 336 #endif // SHARE_VM_OOPS_OOP_HPP