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.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_instanceClassLoader() const; 115 bool is_instanceRef() const; 116 bool is_array() const; 117 bool is_objArray() const; 118 bool is_typeArray() const; 119 120 private: 121 // field addresses in oop 122 void* field_base(int offset) const; 123 124 jbyte* byte_field_addr(int offset) const; 125 jchar* char_field_addr(int offset) const; 126 jboolean* bool_field_addr(int offset) const; 127 jint* int_field_addr(int offset) const; 128 jshort* short_field_addr(int offset) const; 129 jlong* long_field_addr(int offset) const; 130 jfloat* float_field_addr(int offset) const; 131 jdouble* double_field_addr(int offset) const; 132 Metadata** metadata_field_addr(int offset) const; 133 134 public: 135 // Need this as public for garbage collection. 136 template <class T> T* obj_field_addr(int offset) const; 137 138 // Needed for javaClasses 139 address* address_field_addr(int offset) const; 140 141 static bool is_null(oop obj); 142 static bool is_null(narrowOop obj); 143 static bool is_null(Klass* obj); 144 145 // Decode an oop pointer from a narrowOop if compressed. 146 // These are overloaded for oop and narrowOop as are the other functions 147 // below so that they can be called in template functions. 148 static oop decode_heap_oop_not_null(oop v); 149 static oop decode_heap_oop_not_null(narrowOop v); 150 static oop decode_heap_oop(oop v); 151 static oop decode_heap_oop(narrowOop v); 152 153 // Encode an oop pointer to a narrow oop. The or_null versions accept 154 // null oop pointer, others do not in order to eliminate the 155 // null checking branches. 156 static narrowOop encode_heap_oop_not_null(oop v); 157 static narrowOop encode_heap_oop(oop v); 158 159 // Load an oop out of the Java heap 160 static narrowOop load_heap_oop(narrowOop* p); 161 static oop load_heap_oop(oop* p); 162 163 // Load an oop out of Java heap and decode it to an uncompressed oop. 164 static oop load_decode_heap_oop_not_null(narrowOop* p); 165 static oop load_decode_heap_oop_not_null(oop* p); 166 static oop load_decode_heap_oop(narrowOop* p); 167 static oop load_decode_heap_oop(oop* p); 168 169 // Store an oop into the heap. 170 static void store_heap_oop(narrowOop* p, narrowOop v); 171 static void store_heap_oop(oop* p, oop v); 172 173 // Encode oop if UseCompressedOops and store into the heap. 174 static void encode_store_heap_oop_not_null(narrowOop* p, oop v); 175 static void encode_store_heap_oop_not_null(oop* p, oop v); 176 static void encode_store_heap_oop(narrowOop* p, oop v); 177 static void encode_store_heap_oop(oop* p, oop v); 178 179 static void release_store_heap_oop(volatile narrowOop* p, narrowOop v); 180 static void release_store_heap_oop(volatile oop* p, oop v); 181 182 static void release_encode_store_heap_oop_not_null(volatile narrowOop* p, oop v); 183 static void release_encode_store_heap_oop_not_null(volatile oop* p, oop v); 184 static void release_encode_store_heap_oop(volatile narrowOop* p, oop v); 185 static void release_encode_store_heap_oop(volatile oop* p, oop v); 186 187 static oop atomic_exchange_oop(oop exchange_value, volatile HeapWord *dest); 188 static oop atomic_compare_exchange_oop(oop exchange_value, 189 volatile HeapWord *dest, 190 oop compare_value, 191 bool prebarrier = false); 192 193 // Access to fields in a instanceOop through these methods. 194 oop obj_field(int offset) const; 195 volatile oop obj_field_volatile(int offset) const; 196 void obj_field_put(int offset, oop value); 197 void obj_field_put_raw(int offset, oop value); 198 void obj_field_put_volatile(int offset, oop value); 199 200 Metadata* metadata_field(int offset) const; 201 void metadata_field_put(int offset, Metadata* value); 202 203 jbyte byte_field(int offset) const; 204 void byte_field_put(int offset, jbyte contents); 205 206 jchar char_field(int offset) const; 207 void char_field_put(int offset, jchar contents); 208 209 jboolean bool_field(int offset) const; 210 void bool_field_put(int offset, jboolean contents); 211 212 jint int_field(int offset) const; 213 void int_field_put(int offset, jint contents); 214 215 jshort short_field(int offset) const; 216 void short_field_put(int offset, jshort contents); 217 218 jlong long_field(int offset) const; 219 void long_field_put(int offset, jlong contents); 220 221 jfloat float_field(int offset) const; 222 void float_field_put(int offset, jfloat contents); 223 224 jdouble double_field(int offset) const; 225 void double_field_put(int offset, jdouble contents); 226 227 address address_field(int offset) const; 228 void address_field_put(int offset, address contents); 229 230 oop obj_field_acquire(int offset) const; 231 void release_obj_field_put(int offset, oop value); 232 233 jbyte byte_field_acquire(int offset) const; 234 void release_byte_field_put(int offset, jbyte contents); 235 236 jchar char_field_acquire(int offset) const; 237 void release_char_field_put(int offset, jchar contents); 238 239 jboolean bool_field_acquire(int offset) const; 240 void release_bool_field_put(int offset, jboolean contents); 241 242 jint int_field_acquire(int offset) const; 243 void release_int_field_put(int offset, jint contents); 244 245 jshort short_field_acquire(int offset) const; 246 void release_short_field_put(int offset, jshort contents); 247 248 jlong long_field_acquire(int offset) const; 249 void release_long_field_put(int offset, jlong contents); 250 251 jfloat float_field_acquire(int offset) const; 252 void release_float_field_put(int offset, jfloat contents); 253 254 jdouble double_field_acquire(int offset) const; 255 void release_double_field_put(int offset, jdouble contents); 256 257 address address_field_acquire(int offset) const; 258 void release_address_field_put(int offset, address contents); 259 260 // printing functions for VM debugging 261 void print_on(outputStream* st) const; // First level print 262 void print_value_on(outputStream* st) const; // Second level print. 263 void print_address_on(outputStream* st) const; // Address printing 264 265 // printing on default output stream 266 void print(); 267 void print_value(); 268 void print_address(); 269 270 // return the print strings 271 char* print_string(); 272 char* print_value_string(); 273 274 // verification operations 275 void verify_on(outputStream* st); 276 void verify(); 277 278 // locking operations 279 bool is_locked() const; 280 bool is_unlocked() const; 281 bool has_bias_pattern() const; 282 283 // asserts 284 bool is_oop(bool ignore_mark_word = false) const; 285 bool is_oop_or_null(bool ignore_mark_word = false) const; 286 #ifndef PRODUCT 287 bool is_unlocked_oop() const; 288 #endif 289 290 // garbage collection 291 bool is_gc_marked() const; 292 // Apply "MarkSweep::mark_and_push" to (the address of) every non-NULL 293 // reference field in "this". 294 void follow_contents(void); 295 296 #if INCLUDE_ALL_GCS 297 // Parallel Scavenge 298 void push_contents(PSPromotionManager* pm); 299 300 // Parallel Old 301 void update_contents(ParCompactionManager* cm); 302 303 void follow_contents(ParCompactionManager* cm); 304 #endif // INCLUDE_ALL_GCS 305 306 bool is_scavengable() const; 307 308 // Forward pointer operations for scavenge 309 bool is_forwarded() const; 310 311 void forward_to(oop p); 312 bool cas_forward_to(oop p, markOop compare); 313 314 #if INCLUDE_ALL_GCS 315 // Like "forward_to", but inserts the forwarding pointer atomically. 316 // Exactly one thread succeeds in inserting the forwarding pointer, and 317 // this call returns "NULL" for that thread; any other thread has the 318 // value of the forwarding pointer returned and does not modify "this". 319 oop forward_to_atomic(oop p); 320 #endif // INCLUDE_ALL_GCS 321 322 oop forwardee() const; 323 324 // Age of object during scavenge 325 uint age() const; 326 void incr_age(); 327 328 // Adjust all pointers in this object to point at it's forwarded location and 329 // return the size of this oop. This is used by the MarkSweep collector. 330 int adjust_pointers(); 331 332 // mark-sweep support 333 void follow_body(int begin, int end); 334 335 // Fast access to barrier set 336 static BarrierSet* bs() { return _bs; } 337 static void set_bs(BarrierSet* bs) { _bs = bs; } 338 339 // iterators, returns size of object 340 #define OOP_ITERATE_DECL(OopClosureType, nv_suffix) \ 341 int oop_iterate(OopClosureType* blk); \ 342 int oop_iterate(OopClosureType* blk, MemRegion mr); // Only in mr. 343 344 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_DECL) 345 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_DECL) 346 347 #if INCLUDE_ALL_GCS 348 349 #define OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \ 350 int oop_iterate_backwards(OopClosureType* blk); 351 352 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_BACKWARDS_DECL) 353 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_BACKWARDS_DECL) 354 #endif 355 356 int oop_iterate_no_header(OopClosure* bk); 357 int oop_iterate_no_header(OopClosure* bk, MemRegion mr); 358 359 // identity hash; returns the identity hash key (computes it if necessary) 360 // NOTE with the introduction of UseBiasedLocking that identity_hash() might reach a 361 // safepoint if called on a biased object. Calling code must be aware of that. 362 intptr_t identity_hash(); 363 intptr_t slow_identity_hash(); 364 365 // Alternate hashing code if string table is rehashed 366 unsigned int new_hash(juint seed); 367 368 // marks are forwarded to stack when object is locked 369 bool has_displaced_mark() const; 370 markOop displaced_mark() const; 371 void set_displaced_mark(markOop m); 372 373 // for code generation 374 static int mark_offset_in_bytes() { return offset_of(oopDesc, _mark); } 375 static int klass_offset_in_bytes() { return offset_of(oopDesc, _metadata._klass); } 376 static int klass_gap_offset_in_bytes(); 377 }; 378 379 #endif // SHARE_VM_OOPS_OOP_HPP