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 // store into oop with store check 42 template <class T> inline void oop_store(T* p, oop v); 43 template <class T> inline void oop_store(volatile T* p, oop v); 44 45 extern bool always_do_update_barrier; 46 47 // Forward declarations. 48 class OopClosure; 49 class ScanClosure; 50 class FastScanClosure; 51 class FilteringClosure; 52 class BarrierSet; 53 class CMSIsAliveClosure; 54 55 class PSPromotionManager; 56 class ParCompactionManager; 57 58 class oopDesc { 59 friend class VMStructs; 60 friend class JVMCIVMStructs; 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 inline void release_set_mark(markOop m); 78 inline 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 inline void init_mark(); 83 84 inline Klass* klass() const; 85 inline Klass* klass_or_null() const volatile; 86 inline Klass** klass_addr(); 87 inline narrowKlass* compressed_klass_addr(); 88 89 inline void set_klass(Klass* k); 90 91 // For klass field compression 92 inline int klass_gap() const; 93 inline void set_klass_gap(int z); 94 // For when the klass pointer is being used as a linked list "next" field. 95 inline void set_klass_to_list_ptr(oop k); 96 inline 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 inline bool is_a(Klass* k) const; 103 104 // Returns the actual oop size of the object 105 inline 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 inline int size_given_klass(Klass* klass); 110 111 // type test operations (inlined in oop.inline.hpp) 112 inline bool is_instance() const; 113 inline bool is_array() const; 114 inline bool is_objArray() const; 115 inline bool is_typeArray() const; 116 117 // type test operations that don't require inclusion of oop.inline.hpp. 118 bool is_instance_noinline() const; 119 bool is_array_noinline() const; 120 bool is_objArray_noinline() const; 121 bool is_typeArray_noinline() const; 122 123 private: 124 // field addresses in oop 125 inline void* field_base(int offset) const; 126 127 inline jbyte* byte_field_addr(int offset) const; 128 inline jchar* char_field_addr(int offset) const; 129 inline jboolean* bool_field_addr(int offset) const; 130 inline jint* int_field_addr(int offset) const; 131 inline jshort* short_field_addr(int offset) const; 132 inline jlong* long_field_addr(int offset) const; 133 inline jfloat* float_field_addr(int offset) const; 134 inline jdouble* double_field_addr(int offset) const; 135 inline Metadata** metadata_field_addr(int offset) const; 136 137 public: 138 // Need this as public for garbage collection. 139 template <class T> inline T* obj_field_addr(int offset) const; 140 141 // Needed for javaClasses 142 inline address* address_field_addr(int offset) const; 143 144 inline static bool is_null(oop obj) { return obj == NULL; } 145 inline static bool is_null(narrowOop obj) { return obj == 0; } 146 147 // Decode an oop pointer from a narrowOop if compressed. 148 // These are overloaded for oop and narrowOop as are the other functions 149 // below so that they can be called in template functions. 150 static inline oop decode_heap_oop_not_null(oop v) { return v; } 151 static inline oop decode_heap_oop_not_null(narrowOop v); 152 static inline oop decode_heap_oop(oop v) { return v; } 153 static inline oop decode_heap_oop(narrowOop v); 154 155 // Encode an oop pointer to a narrow oop. The or_null versions accept 156 // null oop pointer, others do not in order to eliminate the 157 // null checking branches. 158 static inline narrowOop encode_heap_oop_not_null(oop v); 159 static inline narrowOop encode_heap_oop(oop v); 160 161 // Load an oop out of the Java heap as is without decoding. 162 // Called by GC to check for null before decoding. 163 static inline narrowOop load_heap_oop(narrowOop* p) { return *p; } 164 static inline oop load_heap_oop(oop* p) { return *p; } 165 166 // Load an oop out of Java heap and decode it to an uncompressed oop. 167 static inline oop load_decode_heap_oop_not_null(narrowOop* p); 168 static inline oop load_decode_heap_oop_not_null(oop* p) { return *p; } 169 static inline oop load_decode_heap_oop(narrowOop* p); 170 static inline oop load_decode_heap_oop(oop* p) { return *p; } 171 172 // Store already encoded heap oop into the heap. 173 static inline void store_heap_oop(narrowOop* p, narrowOop v) { *p = v; } 174 static inline void store_heap_oop(oop* p, oop v) { *p = v; } 175 176 // Encode oop if UseCompressedOops and store into the heap. 177 static inline void encode_store_heap_oop_not_null(narrowOop* p, oop v); 178 static inline void encode_store_heap_oop_not_null(oop* p, oop v) { *p = v; } 179 static inline void encode_store_heap_oop(narrowOop* p, oop v); 180 static inline void encode_store_heap_oop(oop* p, oop v) { *p = v; } 181 182 static inline void release_store_heap_oop(volatile narrowOop* p, narrowOop v); 183 static inline void release_store_heap_oop(volatile oop* p, oop v); 184 185 static inline void release_encode_store_heap_oop_not_null(volatile narrowOop* p, oop v); 186 static inline void release_encode_store_heap_oop_not_null(volatile oop* p, oop v); 187 static inline void release_encode_store_heap_oop(volatile narrowOop* p, oop v); 188 static inline void release_encode_store_heap_oop(volatile oop* p, oop v); 189 190 static inline oop atomic_exchange_oop(oop exchange_value, volatile HeapWord *dest); 191 static inline oop atomic_compare_exchange_oop(oop exchange_value, 192 volatile HeapWord *dest, 193 oop compare_value, 194 bool prebarrier = false); 195 196 // Access to fields in a instanceOop through these methods. 197 inline oop obj_field(int offset) const; 198 inline void obj_field_put(int offset, oop value); 199 inline void obj_field_put_raw(int offset, oop value); 200 inline void obj_field_put_volatile(int offset, oop value); 201 202 inline Metadata* metadata_field(int offset) const; 203 inline void metadata_field_put(int offset, Metadata* value); 204 205 inline jbyte byte_field(int offset) const; 206 inline void byte_field_put(int offset, jbyte contents); 207 208 inline jchar char_field(int offset) const; 209 inline void char_field_put(int offset, jchar contents); 210 211 inline jboolean bool_field(int offset) const; 212 inline void bool_field_put(int offset, jboolean contents); 213 214 inline jint int_field(int offset) const; 215 inline void int_field_put(int offset, jint contents); 216 217 inline jshort short_field(int offset) const; 218 inline void short_field_put(int offset, jshort contents); 219 220 inline jlong long_field(int offset) const; 221 inline void long_field_put(int offset, jlong contents); 222 223 inline jfloat float_field(int offset) const; 224 inline void float_field_put(int offset, jfloat contents); 225 226 inline jdouble double_field(int offset) const; 227 inline void double_field_put(int offset, jdouble contents); 228 229 inline address address_field(int offset) const; 230 inline void address_field_put(int offset, address contents); 231 232 inline oop obj_field_acquire(int offset) const; 233 inline void release_obj_field_put(int offset, oop value); 234 235 inline jbyte byte_field_acquire(int offset) const; 236 inline void release_byte_field_put(int offset, jbyte contents); 237 238 inline jchar char_field_acquire(int offset) const; 239 inline void release_char_field_put(int offset, jchar contents); 240 241 inline jboolean bool_field_acquire(int offset) const; 242 inline void release_bool_field_put(int offset, jboolean contents); 243 244 inline jint int_field_acquire(int offset) const; 245 inline void release_int_field_put(int offset, jint contents); 246 247 inline jshort short_field_acquire(int offset) const; 248 inline void release_short_field_put(int offset, jshort contents); 249 250 inline jlong long_field_acquire(int offset) const; 251 inline void release_long_field_put(int offset, jlong contents); 252 253 inline jfloat float_field_acquire(int offset) const; 254 inline void release_float_field_put(int offset, jfloat contents); 255 256 inline jdouble double_field_acquire(int offset) const; 257 inline void release_double_field_put(int offset, jdouble contents); 258 259 inline address address_field_acquire(int offset) const; 260 inline void release_address_field_put(int offset, address contents); 261 262 // printing functions for VM debugging 263 void print_on(outputStream* st) const; // First level print 264 void print_value_on(outputStream* st) const; // Second level print. 265 void print_address_on(outputStream* st) const; // Address printing 266 267 // printing on default output stream 268 void print(); 269 void print_value(); 270 void print_address(); 271 272 // return the print strings 273 char* print_string(); 274 char* print_value_string(); 275 276 // verification operations 277 void verify_on(outputStream* st); 278 void verify(); 279 280 // locking operations 281 inline bool is_locked() const; 282 inline bool is_unlocked() const; 283 inline bool has_bias_pattern() const; 284 285 // asserts 286 inline bool is_oop(bool ignore_mark_word = false) const; 287 inline bool is_oop_or_null(bool ignore_mark_word = false) const; 288 #ifndef PRODUCT 289 inline bool is_unlocked_oop() const; 290 #endif 291 292 // garbage collection 293 inline bool is_gc_marked() const; 294 295 inline bool is_scavengable() const; 296 297 // Forward pointer operations for scavenge 298 inline bool is_forwarded() const; 299 300 inline void forward_to(oop p); 301 inline bool cas_forward_to(oop p, markOop compare); 302 303 #if INCLUDE_ALL_GCS 304 // Like "forward_to", but inserts the forwarding pointer atomically. 305 // Exactly one thread succeeds in inserting the forwarding pointer, and 306 // this call returns "NULL" for that thread; any other thread has the 307 // value of the forwarding pointer returned and does not modify "this". 308 inline oop forward_to_atomic(oop p); 309 #endif // INCLUDE_ALL_GCS 310 311 inline oop forwardee() const; 312 313 // Age of object during scavenge 314 inline uint age() const; 315 inline void incr_age(); 316 317 // mark-sweep support 318 void follow_body(int begin, int end); 319 320 // Fast access to barrier set 321 static BarrierSet* bs() { return _bs; } 322 static void set_bs(BarrierSet* bs) { _bs = bs; } 323 324 // Garbage Collection support 325 326 // Mark Sweep 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 inline int ms_adjust_pointers(); 330 #if INCLUDE_ALL_GCS 331 // Parallel Compact 332 inline void pc_follow_contents(ParCompactionManager* cm); 333 inline void pc_update_contents(ParCompactionManager* cm); 334 // Parallel Scavenge 335 inline void ps_push_contents(PSPromotionManager* pm); 336 #endif 337 338 339 // iterators, returns size of object 340 #define OOP_ITERATE_DECL(OopClosureType, nv_suffix) \ 341 inline void oop_iterate(OopClosureType* blk); \ 342 inline void 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 #define OOP_ITERATE_SIZE_DECL(OopClosureType, nv_suffix) \ 348 inline int oop_iterate_size(OopClosureType* blk); \ 349 inline int oop_iterate_size(OopClosureType* blk, MemRegion mr); // Only in mr. 350 351 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_SIZE_DECL) 352 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_SIZE_DECL) 353 354 355 #if INCLUDE_ALL_GCS 356 357 #define OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \ 358 inline void 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) 362 363 #endif // INCLUDE_ALL_GCS 364 365 inline int oop_iterate_no_header(OopClosure* bk); 366 inline int oop_iterate_no_header(OopClosure* bk, MemRegion mr); 367 368 // identity hash; returns the identity hash key (computes it if necessary) 369 // NOTE with the introduction of UseBiasedLocking that identity_hash() might reach a 370 // safepoint if called on a biased object. Calling code must be aware of that. 371 inline intptr_t identity_hash(); 372 intptr_t slow_identity_hash(); 373 374 // Alternate hashing code if string table is rehashed 375 unsigned int new_hash(juint seed); 376 377 // marks are forwarded to stack when object is locked 378 inline bool has_displaced_mark() const; 379 inline markOop displaced_mark() const; 380 inline void set_displaced_mark(markOop m); 381 382 static bool has_klass_gap(); 383 384 // for code generation 385 static int mark_offset_in_bytes() { return offset_of(oopDesc, _mark); } 386 static int klass_offset_in_bytes() { return offset_of(oopDesc, _metadata._klass); } 387 static int klass_gap_offset_in_bytes() { 388 assert(has_klass_gap(), "only applicable to compressed klass pointers"); 389 return klass_offset_in_bytes() + sizeof(narrowKlass); 390 } 391 }; 392 393 #endif // SHARE_VM_OOPS_OOP_HPP