oop.hpp revision 1472:c18cbe5936b8
1/* 2 * Copyright (c) 1997, 2009, 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// oopDesc is the top baseclass for objects classes. The {name}Desc classes describe 26// the format of Java objects so the fields can be accessed from C++. 27// oopDesc is abstract. 28// (see oopHierarchy for complete oop class hierarchy) 29// 30// no virtual functions allowed 31 32// store into oop with store check 33template <class T> inline void oop_store(T* p, oop v); 34template <class T> inline void oop_store(volatile T* p, oop v); 35 36// store into oop without store check 37template <class T> inline void oop_store_without_check(T* p, oop v); 38template <class T> inline void oop_store_without_check(volatile T* p, oop v); 39 40extern bool always_do_update_barrier; 41 42// Forward declarations. 43class OopClosure; 44class ScanClosure; 45class FastScanClosure; 46class FilteringClosure; 47class BarrierSet; 48class CMSIsAliveClosure; 49 50class PSPromotionManager; 51class ParCompactionManager; 52 53class oopDesc { 54 friend class VMStructs; 55 private: 56 volatile markOop _mark; 57 union _metadata { 58 wideKlassOop _klass; 59 narrowOop _compressed_klass; 60 } _metadata; 61 62 // Fast access to barrier set. Must be initialized. 63 static BarrierSet* _bs; 64 65 public: 66 markOop mark() const { return _mark; } 67 markOop* mark_addr() const { return (markOop*) &_mark; } 68 69 void set_mark(volatile markOop m) { _mark = m; } 70 71 void release_set_mark(markOop m); 72 markOop cas_set_mark(markOop new_mark, markOop old_mark); 73 74 // Used only to re-initialize the mark word (e.g., of promoted 75 // objects during a GC) -- requires a valid klass pointer 76 void init_mark(); 77 78 klassOop klass() const; 79 klassOop klass_or_null() const volatile; 80 oop* klass_addr(); 81 narrowOop* compressed_klass_addr(); 82 83 void set_klass(klassOop k); 84 85 // For klass field compression 86 int klass_gap() const; 87 void set_klass_gap(int z); 88 // For when the klass pointer is being used as a linked list "next" field. 89 void set_klass_to_list_ptr(oop k); 90 91 // size of object header, aligned to platform wordSize 92 static int header_size() { return sizeof(oopDesc)/HeapWordSize; } 93 94 Klass* blueprint() const; 95 96 // Returns whether this is an instance of k or an instance of a subclass of k 97 bool is_a(klassOop k) const; 98 99 // Returns the actual oop size of the object 100 int size(); 101 102 // Sometimes (for complicated concurrency-related reasons), it is useful 103 // to be able to figure out the size of an object knowing its klass. 104 int size_given_klass(Klass* klass); 105 106 // Some perm gen objects are not parseble immediately after 107 // installation of their klass pointer. 108 bool is_parsable(); 109 110 // Some perm gen objects that have been allocated and initialized 111 // can be changed by the VM when not at a safe point (class rededfinition 112 // is an example). Such objects should not be examined by the 113 // concurrent processing of a garbage collector if is_conc_safe() 114 // returns false. 115 bool is_conc_safe(); 116 117 // type test operations (inlined in oop.inline.h) 118 bool is_instance() const; 119 bool is_instanceRef() const; 120 bool is_array() const; 121 bool is_objArray() const; 122 bool is_symbol() const; 123 bool is_klass() const; 124 bool is_thread() const; 125 bool is_method() const; 126 bool is_constMethod() const; 127 bool is_methodData() const; 128 bool is_constantPool() const; 129 bool is_constantPoolCache() const; 130 bool is_typeArray() const; 131 bool is_javaArray() const; 132 bool is_compiledICHolder() const; 133 134 private: 135 // field addresses in oop 136 void* field_base(int offset) const; 137 138 jbyte* byte_field_addr(int offset) const; 139 jchar* char_field_addr(int offset) const; 140 jboolean* bool_field_addr(int offset) const; 141 jint* int_field_addr(int offset) const; 142 jshort* short_field_addr(int offset) const; 143 jlong* long_field_addr(int offset) const; 144 jfloat* float_field_addr(int offset) const; 145 jdouble* double_field_addr(int offset) const; 146 address* address_field_addr(int offset) const; 147 148 public: 149 // Need this as public for garbage collection. 150 template <class T> T* obj_field_addr(int offset) const; 151 152 // Oop encoding heap max 153 static const uint64_t OopEncodingHeapMax = 154 (uint64_t(max_juint) + 1) << LogMinObjAlignmentInBytes; 155 156 static bool is_null(oop obj); 157 static bool is_null(narrowOop obj); 158 159 // Decode an oop pointer from a narrowOop if compressed. 160 // These are overloaded for oop and narrowOop as are the other functions 161 // below so that they can be called in template functions. 162 static oop decode_heap_oop_not_null(oop v); 163 static oop decode_heap_oop_not_null(narrowOop v); 164 static oop decode_heap_oop(oop v); 165 static oop decode_heap_oop(narrowOop v); 166 167 // Encode an oop pointer to a narrow oop. The or_null versions accept 168 // null oop pointer, others do not in order to eliminate the 169 // null checking branches. 170 static narrowOop encode_heap_oop_not_null(oop v); 171 static narrowOop encode_heap_oop(oop v); 172 173 // Load an oop out of the Java heap 174 static narrowOop load_heap_oop(narrowOop* p); 175 static oop load_heap_oop(oop* p); 176 177 // Load an oop out of Java heap and decode it to an uncompressed oop. 178 static oop load_decode_heap_oop_not_null(narrowOop* p); 179 static oop load_decode_heap_oop_not_null(oop* p); 180 static oop load_decode_heap_oop(narrowOop* p); 181 static oop load_decode_heap_oop(oop* p); 182 183 // Store an oop into the heap. 184 static void store_heap_oop(narrowOop* p, narrowOop v); 185 static void store_heap_oop(oop* p, oop v); 186 187 // Encode oop if UseCompressedOops and store into the heap. 188 static void encode_store_heap_oop_not_null(narrowOop* p, oop v); 189 static void encode_store_heap_oop_not_null(oop* p, oop v); 190 static void encode_store_heap_oop(narrowOop* p, oop v); 191 static void encode_store_heap_oop(oop* p, oop v); 192 193 static void release_store_heap_oop(volatile narrowOop* p, narrowOop v); 194 static void release_store_heap_oop(volatile oop* p, oop v); 195 196 static void release_encode_store_heap_oop_not_null(volatile narrowOop* p, oop v); 197 static void release_encode_store_heap_oop_not_null(volatile oop* p, oop v); 198 static void release_encode_store_heap_oop(volatile narrowOop* p, oop v); 199 static void release_encode_store_heap_oop(volatile oop* p, oop v); 200 201 static oop atomic_exchange_oop(oop exchange_value, volatile HeapWord *dest); 202 static oop atomic_compare_exchange_oop(oop exchange_value, 203 volatile HeapWord *dest, 204 oop compare_value); 205 206 // Access to fields in a instanceOop through these methods. 207 oop obj_field(int offset) const; 208 void obj_field_put(int offset, oop value); 209 void obj_field_raw_put(int offset, oop value); 210 211 jbyte byte_field(int offset) const; 212 void byte_field_put(int offset, jbyte contents); 213 214 jchar char_field(int offset) const; 215 void char_field_put(int offset, jchar contents); 216 217 jboolean bool_field(int offset) const; 218 void bool_field_put(int offset, jboolean contents); 219 220 jint int_field(int offset) const; 221 void int_field_put(int offset, jint contents); 222 223 jshort short_field(int offset) const; 224 void short_field_put(int offset, jshort contents); 225 226 jlong long_field(int offset) const; 227 void long_field_put(int offset, jlong contents); 228 229 jfloat float_field(int offset) const; 230 void float_field_put(int offset, jfloat contents); 231 232 jdouble double_field(int offset) const; 233 void double_field_put(int offset, jdouble contents); 234 235 address address_field(int offset) const; 236 void address_field_put(int offset, address contents); 237 238 oop obj_field_acquire(int offset) const; 239 void release_obj_field_put(int offset, oop value); 240 241 jbyte byte_field_acquire(int offset) const; 242 void release_byte_field_put(int offset, jbyte contents); 243 244 jchar char_field_acquire(int offset) const; 245 void release_char_field_put(int offset, jchar contents); 246 247 jboolean bool_field_acquire(int offset) const; 248 void release_bool_field_put(int offset, jboolean contents); 249 250 jint int_field_acquire(int offset) const; 251 void release_int_field_put(int offset, jint contents); 252 253 jshort short_field_acquire(int offset) const; 254 void release_short_field_put(int offset, jshort contents); 255 256 jlong long_field_acquire(int offset) const; 257 void release_long_field_put(int offset, jlong contents); 258 259 jfloat float_field_acquire(int offset) const; 260 void release_float_field_put(int offset, jfloat contents); 261 262 jdouble double_field_acquire(int offset) const; 263 void release_double_field_put(int offset, jdouble contents); 264 265 address address_field_acquire(int offset) const; 266 void release_address_field_put(int offset, address contents); 267 268 // printing functions for VM debugging 269 void print_on(outputStream* st) const; // First level print 270 void print_value_on(outputStream* st) const; // Second level print. 271 void print_address_on(outputStream* st) const; // Address printing 272 273 // printing on default output stream 274 void print(); 275 void print_value(); 276 void print_address(); 277 278 // return the print strings 279 char* print_string(); 280 char* print_value_string(); 281 282 // verification operations 283 void verify_on(outputStream* st); 284 void verify(); 285 void verify_old_oop(oop* p, bool allow_dirty); 286 void verify_old_oop(narrowOop* p, bool allow_dirty); 287 288 // tells whether this oop is partially constructed (gc during class loading) 289 bool partially_loaded(); 290 void set_partially_loaded(); 291 292 // locking operations 293 bool is_locked() const; 294 bool is_unlocked() const; 295 bool has_bias_pattern() const; 296 297 // asserts 298 bool is_oop(bool ignore_mark_word = false) const; 299 bool is_oop_or_null(bool ignore_mark_word = false) const; 300#ifndef PRODUCT 301 bool is_unlocked_oop() const; 302#endif 303 304 // garbage collection 305 bool is_gc_marked() const; 306 // Apply "MarkSweep::mark_and_push" to (the address of) every non-NULL 307 // reference field in "this". 308 void follow_contents(void); 309 void follow_header(void); 310 311#ifndef SERIALGC 312 // Parallel Scavenge 313 void copy_contents(PSPromotionManager* pm); 314 void push_contents(PSPromotionManager* pm); 315 316 // Parallel Old 317 void update_contents(ParCompactionManager* cm); 318 void update_contents(ParCompactionManager* cm, 319 HeapWord* begin_limit, 320 HeapWord* end_limit); 321 void update_contents(ParCompactionManager* cm, 322 klassOop old_klass, 323 HeapWord* begin_limit, 324 HeapWord* end_limit); 325 326 void follow_contents(ParCompactionManager* cm); 327 void follow_header(ParCompactionManager* cm); 328#endif // SERIALGC 329 330 bool is_perm() const; 331 bool is_perm_or_null() const; 332 bool is_scavengable() const; 333 bool is_shared() const; 334 bool is_shared_readonly() const; 335 bool is_shared_readwrite() const; 336 337 // Forward pointer operations for scavenge 338 bool is_forwarded() const; 339 340 void forward_to(oop p); 341 bool cas_forward_to(oop p, markOop compare); 342 343#ifndef SERIALGC 344 // Like "forward_to", but inserts the forwarding pointer atomically. 345 // Exactly one thread succeeds in inserting the forwarding pointer, and 346 // this call returns "NULL" for that thread; any other thread has the 347 // value of the forwarding pointer returned and does not modify "this". 348 oop forward_to_atomic(oop p); 349#endif // SERIALGC 350 351 oop forwardee() const; 352 353 // Age of object during scavenge 354 int age() const; 355 void incr_age(); 356 357 // Adjust all pointers in this object to point at it's forwarded location and 358 // return the size of this oop. This is used by the MarkSweep collector. 359 int adjust_pointers(); 360 void adjust_header(); 361 362#ifndef SERIALGC 363 // Parallel old 364 void update_header(); 365 void update_header(HeapWord* beg_addr, HeapWord* end_addr); 366#endif // SERIALGC 367 368 // mark-sweep support 369 void follow_body(int begin, int end); 370 371 // Fast access to barrier set 372 static BarrierSet* bs() { return _bs; } 373 static void set_bs(BarrierSet* bs) { _bs = bs; } 374 375 // iterators, returns size of object 376#define OOP_ITERATE_DECL(OopClosureType, nv_suffix) \ 377 int oop_iterate(OopClosureType* blk); \ 378 int oop_iterate(OopClosureType* blk, MemRegion mr); // Only in mr. 379 380 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_DECL) 381 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_DECL) 382 383#ifndef SERIALGC 384 385#define OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \ 386 int oop_iterate_backwards(OopClosureType* blk); 387 388 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_BACKWARDS_DECL) 389 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_BACKWARDS_DECL) 390#endif 391 392 void oop_iterate_header(OopClosure* blk); 393 void oop_iterate_header(OopClosure* blk, MemRegion mr); 394 395 // identity hash; returns the identity hash key (computes it if necessary) 396 // NOTE with the introduction of UseBiasedLocking that identity_hash() might reach a 397 // safepoint if called on a biased object. Calling code must be aware of that. 398 intptr_t identity_hash(); 399 intptr_t slow_identity_hash(); 400 401 // marks are forwarded to stack when object is locked 402 bool has_displaced_mark() const; 403 markOop displaced_mark() const; 404 void set_displaced_mark(markOop m); 405 406 // for code generation 407 static int mark_offset_in_bytes() { return offset_of(oopDesc, _mark); } 408 static int klass_offset_in_bytes() { return offset_of(oopDesc, _metadata._klass); } 409 static int klass_gap_offset_in_bytes(); 410}; 411