1 /* 2 * Copyright (c) 1997, 2013, 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/macros.hpp" 33 #include "utilities/top.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 // store into oop with store check 43 template <class T> void oop_store(T* p, oop v); 44 template <class T> void oop_store(volatile T* p, oop v); 45 46 extern bool always_do_update_barrier; 47 48 // Forward declarations. 49 class OopClosure; 50 class ScanClosure; 51 class FastScanClosure; 52 class FilteringClosure; 53 class BarrierSet; 54 class CMSIsAliveClosure; 55 56 class PSPromotionManager; 57 class ParCompactionManager; 58 59 class oopDesc { 60 friend class VMStructs; 61 private: 62 volatile markOop _mark; 63 union _metadata { 64 Klass* _klass; 65 narrowKlass _compressed_klass; 66 } _metadata; 67 68 // Fast access to barrier set. Must be initialized. 69 static BarrierSet* _bs; 70 71 public: 72 markOop mark() const { return _mark; } 73 markOop* mark_addr() const { return (markOop*) &_mark; } 74 75 void set_mark(volatile markOop m) { _mark = m; } 76 77 void release_set_mark(markOop m); 78 markOop cas_set_mark(markOop new_mark, markOop old_mark); 79 80 // Used only to re-initialize the mark word (e.g., of promoted 81 // objects during a GC) -- requires a valid klass pointer 82 void init_mark(); 83 84 Klass* klass() const; 85 Klass* klass_or_null() const volatile; 86 Klass** klass_addr(); 87 narrowKlass* compressed_klass_addr(); 88 89 void set_klass(Klass* k); 90 91 // For klass field compression 92 int klass_gap() const; 93 void set_klass_gap(int z); 94 // For when the klass pointer is being used as a linked list "next" field. 95 void set_klass_to_list_ptr(oop k); 96 oop list_ptr_from_klass(); 97 98 // size of object header, aligned to platform wordSize 99 static int header_size() { return sizeof(oopDesc)/HeapWordSize; } 100 101 // Returns whether this is an instance of k or an instance of a subclass of k 102 bool is_a(Klass* k) const; 103 104 // Returns the actual oop size of the object 105 int size(); 106 107 // Sometimes (for complicated concurrency-related reasons), it is useful 108 // to be able to figure out the size of an object knowing its klass. 109 int size_given_klass(Klass* klass); 110 111 // type test operations (inlined in oop.inline.h) 112 bool is_instance() const; 113 bool is_instanceMirror() const; 114 bool is_instanceRef() const; 115 bool is_array() const; 116 bool is_objArray() const; 117 bool is_typeArray() const; 118 119 private: 120 // field addresses in oop 121 void* field_base(int offset) const; 122 123 jbyte* byte_field_addr(int offset) const; 124 jchar* char_field_addr(int offset) const; 125 jboolean* bool_field_addr(int offset) const; 126 jint* int_field_addr(int offset) const; 127 jshort* short_field_addr(int offset) const; 128 jlong* long_field_addr(int offset) const; 129 jfloat* float_field_addr(int offset) const; 130 jdouble* double_field_addr(int offset) const; 131 Metadata** metadata_field_addr(int offset) const; 132 133 public: 134 // Need this as public for garbage collection. 135 template <class T> T* obj_field_addr(int offset) const; 136 137 // Needed for javaClasses 138 address* address_field_addr(int offset) const; 139 140 static bool is_null(oop obj); 141 static bool is_null(narrowOop obj); 142 static bool is_null(Klass* obj); 143 144 // Decode an oop pointer from a narrowOop if compressed. 145 // These are overloaded for oop and narrowOop as are the other functions 146 // below so that they can be called in template functions. 147 static oop decode_heap_oop_not_null(oop v); 148 static oop decode_heap_oop_not_null(narrowOop v); 149 static oop decode_heap_oop(oop v); 150 static oop decode_heap_oop(narrowOop v); 151 152 // Encode an oop pointer to a narrow oop. The or_null versions accept 153 // null oop pointer, others do not in order to eliminate the 154 // null checking branches. 155 static narrowOop encode_heap_oop_not_null(oop v); 156 static narrowOop encode_heap_oop(oop v); 157 158 // Load an oop out of the Java heap 159 static narrowOop load_heap_oop(narrowOop* p); 160 static oop load_heap_oop(oop* p); 161 162 // Load an oop out of Java heap and decode it to an uncompressed oop. 163 static oop load_decode_heap_oop_not_null(narrowOop* p); 164 static oop load_decode_heap_oop_not_null(oop* p); 165 static oop load_decode_heap_oop(narrowOop* p); 166 static oop load_decode_heap_oop(oop* p); 167 168 // Store an oop into the heap. 169 static void store_heap_oop(narrowOop* p, narrowOop v); 170 static void store_heap_oop(oop* p, oop v); 171 172 // Encode oop if UseCompressedOops and store into the heap. 173 static void encode_store_heap_oop_not_null(narrowOop* p, oop v); 174 static void encode_store_heap_oop_not_null(oop* p, oop v); 175 static void encode_store_heap_oop(narrowOop* p, oop v); 176 static void encode_store_heap_oop(oop* p, oop v); 177 178 static void release_store_heap_oop(volatile narrowOop* p, narrowOop v); 179 static void release_store_heap_oop(volatile oop* p, oop v); 180 181 static void release_encode_store_heap_oop_not_null(volatile narrowOop* p, oop v); 182 static void release_encode_store_heap_oop_not_null(volatile oop* p, oop v); 183 static void release_encode_store_heap_oop(volatile narrowOop* p, oop v); 184 static void release_encode_store_heap_oop(volatile oop* p, oop v); 185 186 static oop atomic_exchange_oop(oop exchange_value, volatile HeapWord *dest); 187 static oop atomic_compare_exchange_oop(oop exchange_value, 188 volatile HeapWord *dest, 189 oop compare_value, 190 bool prebarrier = false); 191 192 // Access to fields in a instanceOop through these methods. 193 oop obj_field(int offset) const; 194 volatile oop obj_field_volatile(int offset) const; 195 void obj_field_put(int offset, oop value); 196 void obj_field_put_raw(int offset, oop value); 197 void obj_field_put_volatile(int offset, oop value); 198 199 Metadata* metadata_field(int offset) const; 200 void metadata_field_put(int offset, Metadata* value); 201 202 jbyte byte_field(int offset) const; 203 void byte_field_put(int offset, jbyte contents); 204 205 jchar char_field(int offset) const; 206 void char_field_put(int offset, jchar contents); 207 208 jboolean bool_field(int offset) const; 209 void bool_field_put(int offset, jboolean contents); 210 211 jint int_field(int offset) const; 212 void int_field_put(int offset, jint contents); 213 214 jshort short_field(int offset) const; 215 void short_field_put(int offset, jshort contents); 216 217 jlong long_field(int offset) const; 218 void long_field_put(int offset, jlong contents); 219 220 jfloat float_field(int offset) const; 221 void float_field_put(int offset, jfloat contents); 222 223 jdouble double_field(int offset) const; 224 void double_field_put(int offset, jdouble contents); 225 226 address address_field(int offset) const; 227 void address_field_put(int offset, address contents); 228 229 oop obj_field_acquire(int offset) const; 230 void release_obj_field_put(int offset, oop value); 231 232 jbyte byte_field_acquire(int offset) const; 233 void release_byte_field_put(int offset, jbyte contents); 234 235 jchar char_field_acquire(int offset) const; 236 void release_char_field_put(int offset, jchar contents); 237 238 jboolean bool_field_acquire(int offset) const; 239 void release_bool_field_put(int offset, jboolean contents); 240 241 jint int_field_acquire(int offset) const; 242 void release_int_field_put(int offset, jint contents); 243 244 jshort short_field_acquire(int offset) const; 245 void release_short_field_put(int offset, jshort contents); 246 247 jlong long_field_acquire(int offset) const; 248 void release_long_field_put(int offset, jlong contents); 249 250 jfloat float_field_acquire(int offset) const; 251 void release_float_field_put(int offset, jfloat contents); 252 253 jdouble double_field_acquire(int offset) const; 254 void release_double_field_put(int offset, jdouble contents); 255 256 address address_field_acquire(int offset) const; 257 void release_address_field_put(int offset, address contents); 258 259 // printing functions for VM debugging 260 void print_on(outputStream* st) const; // First level print 261 void print_value_on(outputStream* st) const; // Second level print. 262 void print_address_on(outputStream* st) const; // Address printing 263 264 // printing on default output stream 265 void print(); 266 void print_value(); 267 void print_address(); 268 269 // return the print strings 270 char* print_string(); 271 char* print_value_string(); 272 273 // verification operations 274 void verify_on(outputStream* st); 275 void verify(); 276 277 // locking operations 278 bool is_locked() const; 279 bool is_unlocked() const; 280 bool has_bias_pattern() const; 281 282 // asserts 283 bool is_oop(bool ignore_mark_word = false) const; 284 bool is_oop_or_null(bool ignore_mark_word = false) const; 285 #ifndef PRODUCT 286 bool is_unlocked_oop() const; 287 #endif 288 289 // garbage collection 290 bool is_gc_marked() const; 291 // Apply "MarkSweep::mark_and_push" to (the address of) every non-NULL 292 // reference field in "this". 293 void follow_contents(void); 294 295 #if INCLUDE_ALL_GCS 296 // Parallel Scavenge 297 void push_contents(PSPromotionManager* pm); 298 299 // Parallel Old 300 void update_contents(ParCompactionManager* cm); 301 302 void follow_contents(ParCompactionManager* cm); 303 #endif // INCLUDE_ALL_GCS 304 305 bool is_scavengable() const; 306 307 // Forward pointer operations for scavenge 308 bool is_forwarded() const; 309 310 void forward_to(oop p); 311 bool cas_forward_to(oop p, markOop compare); 312 313 #if INCLUDE_ALL_GCS 314 // Like "forward_to", but inserts the forwarding pointer atomically. 315 // Exactly one thread succeeds in inserting the forwarding pointer, and 316 // this call returns "NULL" for that thread; any other thread has the 317 // value of the forwarding pointer returned and does not modify "this". 318 oop forward_to_atomic(oop p); 319 #endif // INCLUDE_ALL_GCS 320 321 oop forwardee() const; 322 323 // Age of object during scavenge 324 uint age() const; 325 void incr_age(); 326 327 // Adjust all pointers in this object to point at it's forwarded location and 328 // return the size of this oop. This is used by the MarkSweep collector. 329 int adjust_pointers(); 330 331 // mark-sweep support 332 void follow_body(int begin, int end); 333 334 // Fast access to barrier set 335 static BarrierSet* bs() { return _bs; } 336 static void set_bs(BarrierSet* bs) { _bs = bs; } 337 338 // iterators, returns size of object 339 #define OOP_ITERATE_DECL(OopClosureType, nv_suffix) \ 340 int oop_iterate(OopClosureType* blk); \ 341 int oop_iterate(OopClosureType* blk, MemRegion mr); // Only in mr. 342 343 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_DECL) 344 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_DECL) 345 346 #if INCLUDE_ALL_GCS 347 348 #define OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \ 349 int oop_iterate_backwards(OopClosureType* blk); 350 351 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_BACKWARDS_DECL) 352 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_BACKWARDS_DECL) 353 #endif 354 355 int oop_iterate_no_header(OopClosure* bk); 356 int oop_iterate_no_header(OopClosure* bk, MemRegion mr); 357 358 // identity hash; returns the identity hash key (computes it if necessary) 359 // NOTE with the introduction of UseBiasedLocking that identity_hash() might reach a 360 // safepoint if called on a biased object. Calling code must be aware of that. 361 intptr_t identity_hash(); 362 intptr_t slow_identity_hash(); 363 364 // Alternate hashing code if string table is rehashed 365 unsigned int new_hash(jint seed); 366 367 // marks are forwarded to stack when object is locked 368 bool has_displaced_mark() const; 369 markOop displaced_mark() const; 370 void set_displaced_mark(markOop m); 371 372 // for code generation 373 static int mark_offset_in_bytes() { return offset_of(oopDesc, _mark); } 374 static int klass_offset_in_bytes() { return offset_of(oopDesc, _metadata._klass); } 375 static int klass_gap_offset_in_bytes(); 376 }; 377 378 #endif // SHARE_VM_OOPS_OOP_HPP