oop.hpp revision 3602:da91efe96a93
1/* 2 * Copyright (c) 1997, 2012, 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.hpp" 31#include "oops/metadata.hpp" 32#include "utilities/top.hpp" 33 34// oopDesc is the top baseclass for objects classes. The {name}Desc classes describe 35// the format of Java objects so the fields can be accessed from C++. 36// oopDesc is abstract. 37// (see oopHierarchy for complete oop class hierarchy) 38// 39// no virtual functions allowed 40 41// store into oop with store check 42template <class T> void oop_store(T* p, oop v); 43template <class T> void oop_store(volatile T* p, oop v); 44 45extern bool always_do_update_barrier; 46 47// Forward declarations. 48class OopClosure; 49class ScanClosure; 50class FastScanClosure; 51class FilteringClosure; 52class BarrierSet; 53class CMSIsAliveClosure; 54 55class PSPromotionManager; 56class ParCompactionManager; 57 58class oopDesc { 59 friend class VMStructs; 60 private: 61 volatile markOop _mark; 62 union _metadata { 63 Klass* _klass; 64 narrowOop _compressed_klass; 65 } _metadata; 66 67 // Fast access to barrier set. Must be initialized. 68 static BarrierSet* _bs; 69 70 public: 71 markOop mark() const { return _mark; } 72 markOop* mark_addr() const { return (markOop*) &_mark; } 73 74 void set_mark(volatile markOop m) { _mark = m; } 75 76 void release_set_mark(markOop m); 77 markOop cas_set_mark(markOop new_mark, markOop old_mark); 78 79 // Used only to re-initialize the mark word (e.g., of promoted 80 // objects during a GC) -- requires a valid klass pointer 81 void init_mark(); 82 83 Klass* klass() const; 84 Klass* klass_or_null() const volatile; 85 Klass** klass_addr(); 86 narrowOop* compressed_klass_addr(); 87 88 void set_klass(Klass* k); 89 90 // For klass field compression 91 int klass_gap() const; 92 void set_klass_gap(int z); 93 // For when the klass pointer is being used as a linked list "next" field. 94 void set_klass_to_list_ptr(oop k); 95 oop list_ptr_from_klass(); 96 97 // size of object header, aligned to platform wordSize 98 static int header_size() { return sizeof(oopDesc)/HeapWordSize; } 99 100 // Returns whether this is an instance of k or an instance of a subclass of k 101 bool is_a(Klass* k) const; 102 103 // Returns the actual oop size of the object 104 int size(); 105 106 // Sometimes (for complicated concurrency-related reasons), it is useful 107 // to be able to figure out the size of an object knowing its klass. 108 int size_given_klass(Klass* klass); 109 110 // type test operations (inlined in oop.inline.h) 111 bool is_instance() const; 112 bool is_instanceMirror() const; 113 bool is_instanceRef() const; 114 bool is_array() const; 115 bool is_objArray() const; 116 bool is_typeArray() const; 117 118 private: 119 // field addresses in oop 120 void* field_base(int offset) const; 121 122 jbyte* byte_field_addr(int offset) const; 123 jchar* char_field_addr(int offset) const; 124 jboolean* bool_field_addr(int offset) const; 125 jint* int_field_addr(int offset) const; 126 jshort* short_field_addr(int offset) const; 127 jlong* long_field_addr(int offset) const; 128 jfloat* float_field_addr(int offset) const; 129 jdouble* double_field_addr(int offset) const; 130 Metadata** metadata_field_addr(int offset) const; 131 132 public: 133 // Need this as public for garbage collection. 134 template <class T> T* obj_field_addr(int offset) const; 135 136 // Needed for javaClasses 137 address* address_field_addr(int offset) const; 138 139 static bool is_null(oop obj); 140 static bool is_null(narrowOop obj); 141 static bool is_null(Klass* obj); 142 143 // Decode an oop pointer from a narrowOop if compressed. 144 // These are overloaded for oop and narrowOop as are the other functions 145 // below so that they can be called in template functions. 146 static oop decode_heap_oop_not_null(oop v); 147 static oop decode_heap_oop_not_null(narrowOop v); 148 static oop decode_heap_oop(oop v); 149 static oop decode_heap_oop(narrowOop v); 150 151 // Encode an oop pointer to a narrow oop. The or_null versions accept 152 // null oop pointer, others do not in order to eliminate the 153 // null checking branches. 154 static narrowOop encode_heap_oop_not_null(oop v); 155 static narrowOop encode_heap_oop(oop v); 156 157 // Load an oop out of the Java heap 158 static narrowOop load_heap_oop(narrowOop* p); 159 static oop load_heap_oop(oop* p); 160 161 // Load an oop out of Java heap and decode it to an uncompressed oop. 162 static oop load_decode_heap_oop_not_null(narrowOop* p); 163 static oop load_decode_heap_oop_not_null(oop* p); 164 static oop load_decode_heap_oop(narrowOop* p); 165 static oop load_decode_heap_oop(oop* p); 166 167 // Store an oop into the heap. 168 static void store_heap_oop(narrowOop* p, narrowOop v); 169 static void store_heap_oop(oop* p, oop v); 170 171 // Encode oop if UseCompressedOops and store into the heap. 172 static void encode_store_heap_oop_not_null(narrowOop* p, oop v); 173 static void encode_store_heap_oop_not_null(oop* p, oop v); 174 static void encode_store_heap_oop(narrowOop* p, oop v); 175 static void encode_store_heap_oop(oop* p, oop v); 176 177 static void release_store_heap_oop(volatile narrowOop* p, narrowOop v); 178 static void release_store_heap_oop(volatile oop* p, oop v); 179 180 static void release_encode_store_heap_oop_not_null(volatile narrowOop* p, oop v); 181 static void release_encode_store_heap_oop_not_null(volatile oop* p, oop v); 182 static void release_encode_store_heap_oop(volatile narrowOop* p, oop v); 183 static void release_encode_store_heap_oop(volatile oop* p, oop v); 184 185 static oop atomic_exchange_oop(oop exchange_value, volatile HeapWord *dest); 186 static oop atomic_compare_exchange_oop(oop exchange_value, 187 volatile HeapWord *dest, 188 oop compare_value, 189 bool prebarrier = false); 190 191 // klass encoding for klass pointer in objects. 192 static narrowOop encode_klass_not_null(Klass* v); 193 static narrowOop encode_klass(Klass* v); 194 195 static Klass* decode_klass_not_null(narrowOop v); 196 static Klass* decode_klass(narrowOop v); 197 198 // Access to fields in a instanceOop through these methods. 199 oop obj_field(int offset) const; 200 volatile oop obj_field_volatile(int offset) const; 201 void obj_field_put(int offset, oop value); 202 void obj_field_put_raw(int offset, oop value); 203 void obj_field_put_volatile(int offset, oop value); 204 205 Metadata* metadata_field(int offset) const; 206 void metadata_field_put(int offset, Metadata* value); 207 208 jbyte byte_field(int offset) const; 209 void byte_field_put(int offset, jbyte contents); 210 211 jchar char_field(int offset) const; 212 void char_field_put(int offset, jchar contents); 213 214 jboolean bool_field(int offset) const; 215 void bool_field_put(int offset, jboolean contents); 216 217 jint int_field(int offset) const; 218 void int_field_put(int offset, jint contents); 219 220 jshort short_field(int offset) const; 221 void short_field_put(int offset, jshort contents); 222 223 jlong long_field(int offset) const; 224 void long_field_put(int offset, jlong contents); 225 226 jfloat float_field(int offset) const; 227 void float_field_put(int offset, jfloat contents); 228 229 jdouble double_field(int offset) const; 230 void double_field_put(int offset, jdouble contents); 231 232 address address_field(int offset) const; 233 void address_field_put(int offset, address contents); 234 235 oop obj_field_acquire(int offset) const; 236 void release_obj_field_put(int offset, oop value); 237 238 jbyte byte_field_acquire(int offset) const; 239 void release_byte_field_put(int offset, jbyte contents); 240 241 jchar char_field_acquire(int offset) const; 242 void release_char_field_put(int offset, jchar contents); 243 244 jboolean bool_field_acquire(int offset) const; 245 void release_bool_field_put(int offset, jboolean contents); 246 247 jint int_field_acquire(int offset) const; 248 void release_int_field_put(int offset, jint contents); 249 250 jshort short_field_acquire(int offset) const; 251 void release_short_field_put(int offset, jshort contents); 252 253 jlong long_field_acquire(int offset) const; 254 void release_long_field_put(int offset, jlong contents); 255 256 jfloat float_field_acquire(int offset) const; 257 void release_float_field_put(int offset, jfloat contents); 258 259 jdouble double_field_acquire(int offset) const; 260 void release_double_field_put(int offset, jdouble contents); 261 262 address address_field_acquire(int offset) const; 263 void release_address_field_put(int offset, address contents); 264 265 // printing functions for VM debugging 266 void print_on(outputStream* st) const; // First level print 267 void print_value_on(outputStream* st) const; // Second level print. 268 void print_address_on(outputStream* st) const; // Address printing 269 270 // printing on default output stream 271 void print(); 272 void print_value(); 273 void print_address(); 274 275 // return the print strings 276 char* print_string(); 277 char* print_value_string(); 278 279 // verification operations 280 void verify_on(outputStream* st); 281 void verify(); 282 283 // locking operations 284 bool is_locked() const; 285 bool is_unlocked() const; 286 bool has_bias_pattern() const; 287 288 // asserts 289 bool is_oop(bool ignore_mark_word = false) const; 290 bool is_oop_or_null(bool ignore_mark_word = false) const; 291#ifndef PRODUCT 292 bool is_unlocked_oop() const; 293#endif 294 295 // garbage collection 296 bool is_gc_marked() const; 297 // Apply "MarkSweep::mark_and_push" to (the address of) every non-NULL 298 // reference field in "this". 299 void follow_contents(void); 300 301#ifndef SERIALGC 302 // Parallel Scavenge 303 void push_contents(PSPromotionManager* pm); 304 305 // Parallel Old 306 void update_contents(ParCompactionManager* cm); 307 308 void follow_contents(ParCompactionManager* cm); 309#endif // SERIALGC 310 311 bool is_scavengable() const; 312 313 // Forward pointer operations for scavenge 314 bool is_forwarded() const; 315 316 void forward_to(oop p); 317 bool cas_forward_to(oop p, markOop compare); 318 319#ifndef SERIALGC 320 // Like "forward_to", but inserts the forwarding pointer atomically. 321 // Exactly one thread succeeds in inserting the forwarding pointer, and 322 // this call returns "NULL" for that thread; any other thread has the 323 // value of the forwarding pointer returned and does not modify "this". 324 oop forward_to_atomic(oop p); 325#endif // SERIALGC 326 327 oop forwardee() const; 328 329 // Age of object during scavenge 330 int age() const; 331 void incr_age(); 332 333 // Adjust all pointers in this object to point at it's forwarded location and 334 // return the size of this oop. This is used by the MarkSweep collector. 335 int adjust_pointers(); 336 337#ifndef SERIALGC 338 // Parallel old 339 void update_header(ParCompactionManager* cm); 340#endif // SERIALGC 341 342 // mark-sweep support 343 void follow_body(int begin, int end); 344 345 // Fast access to barrier set 346 static BarrierSet* bs() { return _bs; } 347 static void set_bs(BarrierSet* bs) { _bs = bs; } 348 349 // iterators, returns size of object 350#define OOP_ITERATE_DECL(OopClosureType, nv_suffix) \ 351 int oop_iterate(OopClosureType* blk); \ 352 int oop_iterate(OopClosureType* blk, MemRegion mr); // Only in mr. 353 354 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_DECL) 355 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_DECL) 356 357#ifndef SERIALGC 358 359#define OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \ 360 int oop_iterate_backwards(OopClosureType* blk); 361 362 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_BACKWARDS_DECL) 363 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_BACKWARDS_DECL) 364#endif 365 366 int oop_iterate_no_header(OopClosure* bk); 367 int oop_iterate_no_header(OopClosure* bk, MemRegion mr); 368 369 // identity hash; returns the identity hash key (computes it if necessary) 370 // NOTE with the introduction of UseBiasedLocking that identity_hash() might reach a 371 // safepoint if called on a biased object. Calling code must be aware of that. 372 intptr_t identity_hash(); 373 intptr_t slow_identity_hash(); 374 375 // Alternate hashing code if string table is rehashed 376 unsigned int new_hash(jint seed); 377 378 // marks are forwarded to stack when object is locked 379 bool has_displaced_mark() const; 380 markOop displaced_mark() const; 381 void set_displaced_mark(markOop m); 382 383 // for code generation 384 static int mark_offset_in_bytes() { return offset_of(oopDesc, _mark); } 385 static int klass_offset_in_bytes() { return offset_of(oopDesc, _metadata._klass); } 386 static int klass_gap_offset_in_bytes(); 387}; 388 389#endif // SHARE_VM_OOPS_OOP_HPP 390