1 /* 2 * Copyright (c) 1997, 2014, 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 "memory/specialized_oop_closures.inline.hpp" 31 #include "oops/metadata.hpp" 32 #include "utilities/macros.hpp" 33 #include "utilities/top.hpp" 34 #include "utilities/templateIdioms.hpp" 35 36 // oopDesc is the top baseclass for objects classes. The {name}Desc classes describe 37 // the format of Java objects so the fields can be accessed from C++. 38 // oopDesc is abstract. 39 // (see oopHierarchy for complete oop class hierarchy) 40 // 41 // no virtual functions allowed 42 43 // store into oop with store check 44 template <class T> void oop_store(T* p, oop v); 45 template <class T> void oop_store(volatile T* p, oop v); 46 47 extern bool always_do_update_barrier; 48 49 // Forward declarations. 50 class OopClosure; 51 class ScanClosure; 52 class FastScanClosure; 53 class FilteringClosure; 54 class BarrierSet; 55 class CMSIsAliveClosure; 56 57 class PSPromotionManager; 58 class ParCompactionManager; 59 60 class oopDesc { 61 friend class VMStructs; 62 private: 63 volatile markOop _mark; 64 union _metadata { 65 Klass* _klass; 66 narrowKlass _compressed_klass; 67 } _metadata; 68 69 // Fast access to barrier set. Must be initialized. 70 static BarrierSet* _bs; 71 72 public: 73 markOop mark() const { return _mark; } 74 markOop* mark_addr() const { return (markOop*) &_mark; } 75 76 void set_mark(volatile markOop m) { _mark = m; } 77 78 void release_set_mark(markOop m); 79 markOop cas_set_mark(markOop new_mark, markOop old_mark); 80 81 // Used only to re-initialize the mark word (e.g., of promoted 82 // objects during a GC) -- requires a valid klass pointer 83 void init_mark(); 84 85 Klass* klass() const; 86 Klass* klass_or_null() const volatile; 87 Klass** klass_addr(); 88 narrowKlass* compressed_klass_addr(); 89 90 void set_klass(Klass* k); 91 92 // For klass field compression 93 int klass_gap() const; 94 void set_klass_gap(int z); 95 // For when the klass pointer is being used as a linked list "next" field. 96 void set_klass_to_list_ptr(oop k); 97 oop list_ptr_from_klass(); 98 99 // size of object header, aligned to platform wordSize 100 static int header_size() { return sizeof(oopDesc)/HeapWordSize; } 101 102 // Returns whether this is an instance of k or an instance of a subclass of k 103 bool is_a(Klass* k) const; 104 105 // Returns the actual oop size of the object 106 int size(); 107 108 // Sometimes (for complicated concurrency-related reasons), it is useful 109 // to be able to figure out the size of an object knowing its klass. 110 int size_given_klass(Klass* klass); 111 112 // type test operations (inlined in oop.inline.h) 113 bool is_instance() const; 114 bool is_instanceMirror() const; 115 bool is_instanceClassLoader() const; 116 bool is_instanceRef() const; 117 bool is_array() const; 118 bool is_objArray() const; 119 bool is_typeArray() const; 120 121 private: 122 // field addresses in oop 123 void* field_base(int offset) const; 124 125 jbyte* byte_field_addr(int offset) const; 126 jchar* char_field_addr(int offset) const; 127 jboolean* bool_field_addr(int offset) const; 128 jint* int_field_addr(int offset) const; 129 jshort* short_field_addr(int offset) const; 130 jlong* long_field_addr(int offset) const; 131 jfloat* float_field_addr(int offset) const; 132 jdouble* double_field_addr(int offset) const; 133 Metadata** metadata_field_addr(int offset) const; 134 135 public: 136 // Need this as public for garbage collection. 137 template <class T> T* obj_field_addr(int offset) const; 138 139 // Needed for javaClasses 140 address* address_field_addr(int offset) const; 141 142 static bool is_null(oop obj); 143 static bool is_null(narrowOop obj); 144 static bool is_null(Klass* obj); 145 146 // Decode an oop pointer from a narrowOop if compressed. 147 // These are overloaded for oop and narrowOop as are the other functions 148 // below so that they can be called in template functions. 149 static oop decode_heap_oop_not_null(oop v); 150 static oop decode_heap_oop_not_null(narrowOop v); 151 static oop decode_heap_oop(oop v); 152 static oop decode_heap_oop(narrowOop v); 153 154 // Encode an oop pointer to a narrow oop. The or_null versions accept 155 // null oop pointer, others do not in order to eliminate the 156 // null checking branches. 157 static narrowOop encode_heap_oop_not_null(oop v); 158 static narrowOop encode_heap_oop(oop v); 159 160 // Load an oop out of the Java heap 161 static narrowOop load_heap_oop(narrowOop* p); 162 static oop load_heap_oop(oop* p); 163 164 // Load an oop out of Java heap and decode it to an uncompressed oop. 165 static oop load_decode_heap_oop_not_null(narrowOop* p); 166 static oop load_decode_heap_oop_not_null(oop* p); 167 static oop load_decode_heap_oop(narrowOop* p); 168 static oop load_decode_heap_oop(oop* p); 169 170 // Store an oop into the heap. 171 static void store_heap_oop(narrowOop* p, narrowOop v); 172 static void store_heap_oop(oop* p, oop v); 173 174 // Encode oop if UseCompressedOops and store into the heap. 175 static void encode_store_heap_oop_not_null(narrowOop* p, oop v); 176 static void encode_store_heap_oop_not_null(oop* p, oop v); 177 static void encode_store_heap_oop(narrowOop* p, oop v); 178 static void encode_store_heap_oop(oop* p, oop v); 179 180 static void release_store_heap_oop(volatile narrowOop* p, narrowOop v); 181 static void release_store_heap_oop(volatile oop* p, oop v); 182 183 static void release_encode_store_heap_oop_not_null(volatile narrowOop* p, oop v); 184 static void release_encode_store_heap_oop_not_null(volatile oop* p, oop v); 185 static void release_encode_store_heap_oop(volatile narrowOop* p, oop v); 186 static void release_encode_store_heap_oop(volatile oop* p, oop v); 187 188 static oop atomic_exchange_oop(oop exchange_value, volatile HeapWord *dest); 189 static oop atomic_compare_exchange_oop(oop exchange_value, 190 volatile HeapWord *dest, 191 oop compare_value, 192 bool prebarrier = false); 193 194 // Access to fields in a instanceOop through these methods. 195 oop obj_field(int offset) const; 196 volatile oop obj_field_volatile(int offset) const; 197 void obj_field_put(int offset, oop value); 198 void obj_field_put_raw(int offset, oop value); 199 void obj_field_put_volatile(int offset, oop value); 200 201 Metadata* metadata_field(int offset) const; 202 void metadata_field_put(int offset, Metadata* value); 203 204 jbyte byte_field(int offset) const; 205 void byte_field_put(int offset, jbyte contents); 206 207 jchar char_field(int offset) const; 208 void char_field_put(int offset, jchar contents); 209 210 jboolean bool_field(int offset) const; 211 void bool_field_put(int offset, jboolean contents); 212 213 jint int_field(int offset) const; 214 void int_field_put(int offset, jint contents); 215 216 jshort short_field(int offset) const; 217 void short_field_put(int offset, jshort contents); 218 219 jlong long_field(int offset) const; 220 void long_field_put(int offset, jlong contents); 221 222 jfloat float_field(int offset) const; 223 void float_field_put(int offset, jfloat contents); 224 225 jdouble double_field(int offset) const; 226 void double_field_put(int offset, jdouble contents); 227 228 address address_field(int offset) const; 229 void address_field_put(int offset, address contents); 230 231 oop obj_field_acquire(int offset) const; 232 void release_obj_field_put(int offset, oop value); 233 234 jbyte byte_field_acquire(int offset) const; 235 void release_byte_field_put(int offset, jbyte contents); 236 237 jchar char_field_acquire(int offset) const; 238 void release_char_field_put(int offset, jchar contents); 239 240 jboolean bool_field_acquire(int offset) const; 241 void release_bool_field_put(int offset, jboolean contents); 242 243 jint int_field_acquire(int offset) const; 244 void release_int_field_put(int offset, jint contents); 245 246 jshort short_field_acquire(int offset) const; 247 void release_short_field_put(int offset, jshort contents); 248 249 jlong long_field_acquire(int offset) const; 250 void release_long_field_put(int offset, jlong contents); 251 252 jfloat float_field_acquire(int offset) const; 253 void release_float_field_put(int offset, jfloat contents); 254 255 jdouble double_field_acquire(int offset) const; 256 void release_double_field_put(int offset, jdouble contents); 257 258 address address_field_acquire(int offset) const; 259 void release_address_field_put(int offset, address contents); 260 261 // printing functions for VM debugging 262 void print_on(outputStream* st) const; // First level print 263 void print_value_on(outputStream* st) const; // Second level print. 264 void print_address_on(outputStream* st) const; // Address printing 265 266 // printing on default output stream 267 void print(); 268 void print_value(); 269 void print_address(); 270 271 // return the print strings 272 char* print_string(); 273 char* print_value_string(); 274 275 // verification operations 276 void verify_on(outputStream* st); 277 void verify(); 278 279 // locking operations 280 bool is_locked() const; 281 bool is_unlocked() const; 282 bool has_bias_pattern() const; 283 284 // asserts 285 bool is_oop(bool ignore_mark_word = false) const; 286 bool is_oop_or_null(bool ignore_mark_word = false) const; 287 #ifndef PRODUCT 288 bool is_unlocked_oop() const; 289 #endif 290 291 // garbage collection 292 bool is_gc_marked() const; 293 // Apply "MarkSweep::mark_and_push" to (the address of) every non-NULL 294 // reference field in "this". 295 void follow_contents(void); 296 297 #if INCLUDE_ALL_GCS 298 // Parallel Scavenge 299 void push_contents(PSPromotionManager* pm); 300 301 // Parallel Old 302 void update_contents(ParCompactionManager* cm); 303 304 void follow_contents(ParCompactionManager* cm); 305 #endif // INCLUDE_ALL_GCS 306 307 bool is_scavengable() const; 308 309 // Forward pointer operations for scavenge 310 bool is_forwarded() const; 311 312 void forward_to(oop p); 313 bool cas_forward_to(oop p, markOop compare); 314 315 #if INCLUDE_ALL_GCS 316 // Like "forward_to", but inserts the forwarding pointer atomically. 317 // Exactly one thread succeeds in inserting the forwarding pointer, and 318 // this call returns "NULL" for that thread; any other thread has the 319 // value of the forwarding pointer returned and does not modify "this". 320 oop forward_to_atomic(oop p); 321 #endif // INCLUDE_ALL_GCS 322 323 oop forwardee() const; 324 325 // Age of object during scavenge 326 uint age() const; 327 void incr_age(); 328 329 // Adjust all pointers in this object to point at it's forwarded location and 330 // return the size of this oop. This is used by the MarkSweep collector. 331 int adjust_pointers(); 332 333 // mark-sweep support 334 void follow_body(int begin, int end); 335 336 // Fast access to barrier set 337 static BarrierSet* bs() { return _bs; } 338 static void set_bs(BarrierSet* bs) { _bs = bs; } 339 340 private: 341 // Dispatch member functions to oop closures 342 343 template <class OopClosureType> 344 typename enable_if<is_kind_of<ExtendedOopClosure, OopClosureType>::value, void>::type 345 do_metadata_if_applicable(OopClosureType *cl); 346 347 template <class OopClosureType> 348 typename enable_if<!is_kind_of<ExtendedOopClosure, OopClosureType>::value, void>::type 349 do_metadata_if_applicable(OopClosureType *cl); 350 351 template <class OopClosureType> 352 int oop_iterate_dispatch_tag(OopClosureType *blk, DispatchTag tag); 353 354 template <class OopClosureType> 355 int oop_iterate_internal(OopClosureType *blk); 356 357 public: 358 template <class OopClosureType> 359 typename enable_if<is_kind_of<ExtendedOopClosure, OopClosureType>::value, int>::type 360 oop_iterate(OopClosureType *blk); 361 362 // iterators, returns size of object 363 364 #define OOP_ITERATE_DECL(OopClosureType, nv_suffix) \ 365 int oop_iterate(OopClosureType* blk); \ 366 int oop_iterate(OopClosureType* blk, MemRegion mr); // Only in mr. 367 368 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_DECL) 369 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_DECL) 370 371 #if INCLUDE_ALL_GCS 372 373 #define OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \ 374 int oop_iterate_backwards(OopClosureType* blk); 375 376 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_BACKWARDS_DECL) 377 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_BACKWARDS_DECL) 378 #endif 379 380 template <class OopClosureType> 381 typename enable_if<is_kind_of<OopClosure, OopClosureType>::value, int>::type 382 oop_iterate_no_header(OopClosureType* bk); 383 384 int oop_iterate_no_header(OopClosure* bk, MemRegion mr); 385 386 // identity hash; returns the identity hash key (computes it if necessary) 387 // NOTE with the introduction of UseBiasedLocking that identity_hash() might reach a 388 // safepoint if called on a biased object. Calling code must be aware of that. 389 intptr_t identity_hash(); 390 intptr_t slow_identity_hash(); 391 392 // Alternate hashing code if string table is rehashed 393 unsigned int new_hash(juint seed); 394 395 // marks are forwarded to stack when object is locked 396 bool has_displaced_mark() const; 397 markOop displaced_mark() const; 398 void set_displaced_mark(markOop m); 399 400 // for code generation 401 static int mark_offset_in_bytes() { return offset_of(oopDesc, _mark); } 402 static int klass_offset_in_bytes() { return offset_of(oopDesc, _metadata._klass); } 403 static int klass_gap_offset_in_bytes(); 404 }; 405 406 #endif // SHARE_VM_OOPS_OOP_HPP