1 /* 2 * Copyright (c) 1997, 2015, 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.hpp) 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 // type test operations that don't require inclusion of oop.inline.hpp. 121 bool is_instance_noinline() const; 122 bool is_instanceMirror_noinline() const; 123 bool is_instanceClassLoader_noline() const; 124 bool is_instanceRef_noline() const; 125 bool is_array_noinline() const; 126 bool is_objArray_noinline() const; 127 bool is_typeArray_noinline() const; 128 129 private: 130 // field addresses in oop 131 void* field_base(int offset) const; 132 133 jbyte* byte_field_addr(int offset) const; 134 jchar* char_field_addr(int offset) const; 135 jboolean* bool_field_addr(int offset) const; 136 jint* int_field_addr(int offset) const; 137 jshort* short_field_addr(int offset) const; 138 jlong* long_field_addr(int offset) const; 139 jfloat* float_field_addr(int offset) const; 140 jdouble* double_field_addr(int offset) const; 141 Metadata** metadata_field_addr(int offset) const; 142 143 public: 144 // Need this as public for garbage collection. 145 template <class T> T* obj_field_addr(int offset) const; 146 147 // Needed for javaClasses 148 address* address_field_addr(int offset) const; 149 150 static bool is_null(oop obj); 151 static bool is_null(narrowOop obj); 152 static bool is_null(Klass* obj); 153 154 // Decode an oop pointer from a narrowOop if compressed. 155 // These are overloaded for oop and narrowOop as are the other functions 156 // below so that they can be called in template functions. 157 static oop decode_heap_oop_not_null(oop v); 158 static oop decode_heap_oop_not_null(narrowOop v); 159 static oop decode_heap_oop(oop v); 160 static oop decode_heap_oop(narrowOop v); 161 162 // Encode an oop pointer to a narrow oop. The or_null versions accept 163 // null oop pointer, others do not in order to eliminate the 164 // null checking branches. 165 static narrowOop encode_heap_oop_not_null(oop v); 166 static narrowOop encode_heap_oop(oop v); 167 168 // Load an oop out of the Java heap 169 static narrowOop load_heap_oop(narrowOop* p); 170 static oop load_heap_oop(oop* p); 171 172 // Load an oop out of Java heap and decode it to an uncompressed oop. 173 static oop load_decode_heap_oop_not_null(narrowOop* p); 174 static oop load_decode_heap_oop_not_null(oop* p); 175 static oop load_decode_heap_oop(narrowOop* p); 176 static oop load_decode_heap_oop(oop* p); 177 178 // Store an oop into the heap. 179 static void store_heap_oop(narrowOop* p, narrowOop v); 180 static void store_heap_oop(oop* p, oop v); 181 182 // Encode oop if UseCompressedOops and store into the heap. 183 static void encode_store_heap_oop_not_null(narrowOop* p, oop v); 184 static void encode_store_heap_oop_not_null(oop* p, oop v); 185 static void encode_store_heap_oop(narrowOop* p, oop v); 186 static void encode_store_heap_oop(oop* p, oop v); 187 188 static void release_store_heap_oop(volatile narrowOop* p, narrowOop v); 189 static void release_store_heap_oop(volatile oop* p, oop v); 190 191 static void release_encode_store_heap_oop_not_null(volatile narrowOop* p, oop v); 192 static void release_encode_store_heap_oop_not_null(volatile oop* p, oop v); 193 static void release_encode_store_heap_oop(volatile narrowOop* p, oop v); 194 static void release_encode_store_heap_oop(volatile oop* p, oop v); 195 196 static oop atomic_exchange_oop(oop exchange_value, volatile HeapWord *dest); 197 static oop atomic_compare_exchange_oop(oop exchange_value, 198 volatile HeapWord *dest, 199 oop compare_value, 200 bool prebarrier = false); 201 202 // Access to fields in a instanceOop through these methods. 203 oop obj_field(int offset) const; 204 void obj_field_put(int offset, oop value); 205 void obj_field_put_raw(int offset, oop value); 206 void obj_field_put_volatile(int offset, oop value); 207 208 Metadata* metadata_field(int offset) const; 209 void metadata_field_put(int offset, Metadata* 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(); 285 286 // locking operations 287 bool is_locked() const; 288 bool is_unlocked() const; 289 bool has_bias_pattern() const; 290 291 // asserts 292 bool is_oop(bool ignore_mark_word = false) const; 293 bool is_oop_or_null(bool ignore_mark_word = false) const; 294 #ifndef PRODUCT 295 bool is_unlocked_oop() const; 296 #endif 297 298 // garbage collection 299 bool is_gc_marked() const; 300 301 bool is_scavengable() const; 302 303 // Forward pointer operations for scavenge 304 bool is_forwarded() const; 305 306 void forward_to(oop p); 307 bool cas_forward_to(oop p, markOop compare); 308 309 #if INCLUDE_ALL_GCS 310 // Like "forward_to", but inserts the forwarding pointer atomically. 311 // Exactly one thread succeeds in inserting the forwarding pointer, and 312 // this call returns "NULL" for that thread; any other thread has the 313 // value of the forwarding pointer returned and does not modify "this". 314 oop forward_to_atomic(oop p); 315 #endif // INCLUDE_ALL_GCS 316 317 oop forwardee() const; 318 319 // Age of object during scavenge 320 uint age() const; 321 void incr_age(); 322 323 324 // mark-sweep support 325 void follow_body(int begin, int end); 326 327 // Fast access to barrier set 328 static BarrierSet* bs() { return _bs; } 329 static void set_bs(BarrierSet* bs) { _bs = bs; } 330 331 // Garbage Collection support 332 333 // Mark Sweep 334 void ms_follow_contents(); 335 // Adjust all pointers in this object to point at it's forwarded location and 336 // return the size of this oop. This is used by the MarkSweep collector. 337 int ms_adjust_pointers(); 338 #if INCLUDE_ALL_GCS 339 // Parallel Compact 340 void pc_follow_contents(ParCompactionManager* pc); 341 void pc_update_contents(); 342 // Parallel Scavenge 343 void ps_push_contents(PSPromotionManager* pm); 344 #endif 345 346 347 // iterators, returns size of object 348 #define OOP_ITERATE_DECL(OopClosureType, nv_suffix) \ 349 int oop_iterate(OopClosureType* blk); \ 350 int oop_iterate(OopClosureType* blk, MemRegion mr); // Only in mr. 351 352 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_DECL) 353 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_DECL) 354 355 #if INCLUDE_ALL_GCS 356 357 #define OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \ 358 int oop_iterate_backwards(OopClosureType* blk); 359 360 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_BACKWARDS_DECL) 361 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_BACKWARDS_DECL) 362 #endif 363 364 int oop_iterate_no_header(OopClosure* bk); 365 int oop_iterate_no_header(OopClosure* bk, MemRegion mr); 366 367 // identity hash; returns the identity hash key (computes it if necessary) 368 // NOTE with the introduction of UseBiasedLocking that identity_hash() might reach a 369 // safepoint if called on a biased object. Calling code must be aware of that. 370 intptr_t identity_hash(); 371 intptr_t slow_identity_hash(); 372 373 // Alternate hashing code if string table is rehashed 374 unsigned int new_hash(juint seed); 375 376 // marks are forwarded to stack when object is locked 377 bool has_displaced_mark() const; 378 markOop displaced_mark() const; 379 void set_displaced_mark(markOop m); 380 381 static bool has_klass_gap(); 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 assert(has_klass_gap(), "only applicable to compressed klass pointers"); 388 return klass_offset_in_bytes() + sizeof(narrowKlass); 389 } 390 }; 391 392 #endif // SHARE_VM_OOPS_OOP_HPP