1 /* 2 * Copyright (c) 1997, 2016, 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 "gc/shared/specialized_oop_closures.hpp" 29 #include "memory/iterator.hpp" 30 #include "memory/memRegion.hpp" 31 #include "oops/metadata.hpp" 32 #include "utilities/macros.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 extern bool always_do_update_barrier; 42 43 // Forward declarations. 44 class OopClosure; 45 class ScanClosure; 46 class FastScanClosure; 47 class FilteringClosure; 48 class BarrierSet; 49 class CMSIsAliveClosure; 50 51 class PSPromotionManager; 52 class ParCompactionManager; 53 54 class oopDesc { 55 friend class VMStructs; 56 friend class JVMCIVMStructs; 57 private: 58 volatile markOop _mark; 59 union _metadata { 60 Klass* _klass; 61 narrowKlass _compressed_klass; 62 } _metadata; 63 64 // Fast access to barrier set. Must be initialized. 65 static BarrierSet* _bs; 66 67 public: 68 markOop mark() const { return _mark; } 69 markOop* mark_addr() const { return (markOop*) &_mark; } 70 71 void set_mark(volatile markOop m) { _mark = m; } 72 73 inline void release_set_mark(markOop m); 74 inline markOop cas_set_mark(markOop new_mark, markOop old_mark); 75 76 // Used only to re-initialize the mark word (e.g., of promoted 77 // objects during a GC) -- requires a valid klass pointer 78 inline void init_mark(); 79 80 inline Klass* klass() const; 81 inline Klass* klass_or_null() const volatile; 82 inline Klass* klass_or_null_acquire() const volatile; 83 inline Klass** klass_addr(); 84 inline narrowKlass* compressed_klass_addr(); 85 86 inline void set_klass(Klass* k); 87 inline void release_set_klass(Klass* k); 88 89 // For klass field compression 90 inline int klass_gap() const; 91 inline void set_klass_gap(int z); 92 // For when the klass pointer is being used as a linked list "next" field. 93 inline void set_klass_to_list_ptr(oop k); 94 inline oop list_ptr_from_klass(); 95 96 // size of object header, aligned to platform wordSize 97 static int header_size() { return sizeof(oopDesc)/HeapWordSize; } 98 99 // Returns whether this is an instance of k or an instance of a subclass of k 100 inline bool is_a(Klass* k) const; 101 102 // Returns the actual oop size of the object 103 inline int size(); 104 105 // Sometimes (for complicated concurrency-related reasons), it is useful 106 // to be able to figure out the size of an object knowing its klass. 107 inline int size_given_klass(Klass* klass); 108 109 // type test operations (inlined in oop.inline.hpp) 110 inline bool is_instance() const; 111 inline bool is_array() const; 112 inline bool is_objArray() const; 113 inline bool is_typeArray() const; 114 115 // type test operations that don't require inclusion of oop.inline.hpp. 116 bool is_instance_noinline() const; 117 bool is_array_noinline() const; 118 bool is_objArray_noinline() const; 119 bool is_typeArray_noinline() const; 120 121 protected: 122 inline oop oop_base() const { return const_cast<oopDesc*>(this); } 123 124 private: 125 // field addresses in oop 126 inline void* field_base(int offset) const; 127 128 inline jbyte* byte_field_addr(int offset) const; 129 inline jchar* char_field_addr(int offset) const; 130 inline jboolean* bool_field_addr(int offset) const; 131 inline jint* int_field_addr(int offset) const; 132 inline jshort* short_field_addr(int offset) const; 133 inline jlong* long_field_addr(int offset) const; 134 inline jfloat* float_field_addr(int offset) const; 135 inline jdouble* double_field_addr(int offset) const; 136 inline Metadata** metadata_field_addr(int offset) const; 137 138 public: 139 // Need this as public for garbage collection. 140 template <class T> inline T* obj_field_addr(int offset) const; 141 142 // Needed for javaClasses 143 inline address* address_field_addr(int offset) const; 144 145 inline static bool is_null(oop obj) { return obj == NULL; } 146 inline static bool is_null(narrowOop obj) { return obj == 0; } 147 148 // Decode an oop pointer from a narrowOop if compressed. 149 // These are overloaded for oop and narrowOop as are the other functions 150 // below so that they can be called in template functions. 151 static inline oop decode_heap_oop_not_null(oop v) { return v; } 152 static inline oop decode_heap_oop_not_null(narrowOop v); 153 static inline oop decode_heap_oop(oop v) { return v; } 154 static inline oop decode_heap_oop(narrowOop v); 155 156 // Encode an oop pointer to a narrow oop. The or_null versions accept 157 // null oop pointer, others do not in order to eliminate the 158 // null checking branches. 159 static inline narrowOop encode_heap_oop_not_null(oop v); 160 static inline narrowOop encode_heap_oop(oop v); 161 162 // Load an oop out of the Java heap as is without decoding. 163 // Called by GC to check for null before decoding. 164 static inline narrowOop load_heap_oop(narrowOop* p); 165 static inline oop load_heap_oop(oop* p); 166 167 // Load an oop out of Java heap and decode it to an uncompressed oop. 168 static inline oop load_decode_heap_oop_not_null(narrowOop* p); 169 static inline oop load_decode_heap_oop_not_null(oop* p); 170 static inline oop load_decode_heap_oop(narrowOop* p); 171 static inline oop load_decode_heap_oop(oop* p); 172 173 // Store already encoded heap oop into the heap. 174 static inline void store_heap_oop(narrowOop* p, narrowOop v); 175 static inline void store_heap_oop(oop* p, oop v); 176 177 // Encode oop if UseCompressedOops and store into the heap. 178 static inline void encode_store_heap_oop_not_null(narrowOop* p, oop v); 179 static inline void encode_store_heap_oop_not_null(oop* p, oop v); 180 static inline void encode_store_heap_oop(narrowOop* p, oop v); 181 static inline void encode_store_heap_oop(oop* p, oop v); 182 183 static oop atomic_exchange_oop(oop exchange_value, volatile HeapWord *dest); 184 static oop atomic_compare_exchange_oop(oop exchange_value, 185 volatile HeapWord *dest, 186 oop compare_value); 187 188 // Access to fields in a instanceOop through these methods. 189 oop obj_field(int offset) const; 190 void obj_field_put(int offset, oop value); 191 void obj_field_put_raw(int offset, oop value); 192 void obj_field_put_volatile(int offset, oop value); 193 194 Metadata* metadata_field(int offset) const; 195 void metadata_field_put(int offset, Metadata* value); 196 197 jbyte byte_field(int offset) const; 198 void byte_field_put(int offset, jbyte contents); 199 200 jchar char_field(int offset) const; 201 void char_field_put(int offset, jchar contents); 202 203 jboolean bool_field(int offset) const; 204 void bool_field_put(int offset, jboolean contents); 205 206 jint int_field(int offset) const; 207 void int_field_put(int offset, jint contents); 208 209 jshort short_field(int offset) const; 210 void short_field_put(int offset, jshort contents); 211 212 jlong long_field(int offset) const; 213 void long_field_put(int offset, jlong contents); 214 215 jfloat float_field(int offset) const; 216 void float_field_put(int offset, jfloat contents); 217 218 jdouble double_field(int offset) const; 219 void double_field_put(int offset, jdouble contents); 220 221 address address_field(int offset) const; 222 void address_field_put(int offset, address contents); 223 224 oop obj_field_acquire(int offset) const; 225 void release_obj_field_put(int offset, oop value); 226 227 jbyte byte_field_acquire(int offset) const; 228 void release_byte_field_put(int offset, jbyte contents); 229 230 jchar char_field_acquire(int offset) const; 231 void release_char_field_put(int offset, jchar contents); 232 233 jboolean bool_field_acquire(int offset) const; 234 void release_bool_field_put(int offset, jboolean contents); 235 236 jint int_field_acquire(int offset) const; 237 void release_int_field_put(int offset, jint contents); 238 239 jshort short_field_acquire(int offset) const; 240 void release_short_field_put(int offset, jshort contents); 241 242 jlong long_field_acquire(int offset) const; 243 void release_long_field_put(int offset, jlong contents); 244 245 jfloat float_field_acquire(int offset) const; 246 void release_float_field_put(int offset, jfloat contents); 247 248 jdouble double_field_acquire(int offset) const; 249 void release_double_field_put(int offset, jdouble contents); 250 251 address address_field_acquire(int offset) const; 252 void release_address_field_put(int offset, address contents); 253 254 // printing functions for VM debugging 255 void print_on(outputStream* st) const; // First level print 256 void print_value_on(outputStream* st) const; // Second level print. 257 void print_address_on(outputStream* st) const; // Address printing 258 259 // printing on default output stream 260 void print(); 261 void print_value(); 262 void print_address(); 263 264 // return the print strings 265 char* print_string(); 266 char* print_value_string(); 267 268 // verification operations 269 void verify_on(outputStream* st); 270 void verify(); 271 272 // locking operations 273 inline bool is_locked() const; 274 inline bool is_unlocked() const; 275 inline bool has_bias_pattern() const; 276 277 // asserts 278 inline bool is_oop(bool ignore_mark_word = false) const; 279 inline bool is_oop_or_null(bool ignore_mark_word = false) const; 280 #ifndef PRODUCT 281 inline bool is_unlocked_oop() const; 282 #endif 283 284 // garbage collection 285 inline bool is_gc_marked() const; 286 287 inline bool is_scavengable() const; 288 289 // Forward pointer operations for scavenge 290 inline bool is_forwarded() const; 291 292 inline void forward_to(oop p); 293 inline bool cas_forward_to(oop p, markOop compare); 294 295 #if INCLUDE_ALL_GCS 296 // Like "forward_to", but inserts the forwarding pointer atomically. 297 // Exactly one thread succeeds in inserting the forwarding pointer, and 298 // this call returns "NULL" for that thread; any other thread has the 299 // value of the forwarding pointer returned and does not modify "this". 300 inline oop forward_to_atomic(oop p); 301 #endif // INCLUDE_ALL_GCS 302 303 inline oop forwardee() const; 304 305 // Age of object during scavenge 306 inline uint age() const; 307 inline void incr_age(); 308 309 // mark-sweep support 310 void follow_body(int begin, int end); 311 312 // Fast access to barrier set 313 static BarrierSet* bs() { return _bs; } 314 static void set_bs(BarrierSet* bs) { _bs = bs; } 315 316 // Garbage Collection support 317 318 // Mark Sweep 319 // Adjust all pointers in this object to point at it's forwarded location and 320 // return the size of this oop. This is used by the MarkSweep collector. 321 inline int ms_adjust_pointers(); 322 #if INCLUDE_ALL_GCS 323 // Parallel Compact 324 inline void pc_follow_contents(ParCompactionManager* cm); 325 inline void pc_update_contents(ParCompactionManager* cm); 326 // Parallel Scavenge 327 inline void ps_push_contents(PSPromotionManager* pm); 328 #endif 329 330 331 // iterators, returns size of object 332 #define OOP_ITERATE_DECL(OopClosureType, nv_suffix) \ 333 inline void oop_iterate(OopClosureType* blk); \ 334 inline void oop_iterate(OopClosureType* blk, MemRegion mr); // Only in mr. 335 336 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_DECL) 337 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_DECL) 338 339 #define OOP_ITERATE_SIZE_DECL(OopClosureType, nv_suffix) \ 340 inline int oop_iterate_size(OopClosureType* blk); \ 341 inline int oop_iterate_size(OopClosureType* blk, MemRegion mr); // Only in mr. 342 343 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_SIZE_DECL) 344 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_SIZE_DECL) 345 346 347 #if INCLUDE_ALL_GCS 348 349 #define OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \ 350 inline void 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) 354 355 #endif // INCLUDE_ALL_GCS 356 357 inline int oop_iterate_no_header(OopClosure* bk); 358 inline int oop_iterate_no_header(OopClosure* bk, MemRegion mr); 359 360 // identity hash; returns the identity hash key (computes it if necessary) 361 // NOTE with the introduction of UseBiasedLocking that identity_hash() might reach a 362 // safepoint if called on a biased object. Calling code must be aware of that. 363 inline intptr_t identity_hash(); 364 intptr_t slow_identity_hash(); 365 366 // Alternate hashing code if string table is rehashed 367 unsigned int new_hash(juint seed); 368 369 // marks are forwarded to stack when object is locked 370 inline bool has_displaced_mark() const; 371 inline markOop displaced_mark() const; 372 inline void set_displaced_mark(markOop m); 373 374 static bool has_klass_gap(); 375 376 // for code generation 377 static int mark_offset_in_bytes() { return offset_of(oopDesc, _mark); } 378 static int klass_offset_in_bytes() { return offset_of(oopDesc, _metadata._klass); } 379 static int klass_gap_offset_in_bytes() { 380 assert(has_klass_gap(), "only applicable to compressed klass pointers"); 381 return klass_offset_in_bytes() + sizeof(narrowKlass); 382 } 383 }; 384 385 #endif // SHARE_VM_OOPS_OOP_HPP