1 /* 2 * Copyright (c) 1997, 2018, 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/access.hpp" 32 #include "oops/metadata.hpp" 33 #include "utilities/macros.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 extern bool always_do_update_barrier; 43 44 // Forward declarations. 45 class OopClosure; 46 class ScanClosure; 47 class FastScanClosure; 48 class FilteringClosure; 49 class BarrierSet; 50 class CMSIsAliveClosure; 51 52 class PSPromotionManager; 53 class ParCompactionManager; 54 55 class oopDesc { 56 friend class VMStructs; 57 friend class JVMCIVMStructs; 58 private: 59 volatile markOop _mark; 60 union _metadata { 61 Klass* _klass; 62 narrowKlass _compressed_klass; 63 } _metadata; 64 65 public: 66 markOop mark() const; 67 markOop* mark_addr() const; 68 69 void set_mark(volatile markOop m); 70 71 inline void release_set_mark(markOop m); 72 inline markOop cas_set_mark(markOop new_mark, markOop old_mark); 73 74 // Used only to re-initialize the mark word (e.g., of promoted 75 // objects during a GC) -- requires a valid klass pointer 76 inline void init_mark(); 77 78 inline Klass* klass() const; 79 inline Klass* klass_or_null() const volatile; 80 inline Klass* klass_or_null_acquire() const volatile; 81 inline Klass** klass_addr(); 82 inline narrowKlass* compressed_klass_addr(); 83 84 inline void set_klass(Klass* k); 85 inline void release_set_klass(Klass* k); 86 87 // For klass field compression 88 inline int klass_gap() const; 89 inline void set_klass_gap(int z); 90 // For when the klass pointer is being used as a linked list "next" field. 91 inline void set_klass_to_list_ptr(oop k); 92 inline oop list_ptr_from_klass(); 93 94 // size of object header, aligned to platform wordSize 95 static int header_size() { return sizeof(oopDesc)/HeapWordSize; } 96 97 // Returns whether this is an instance of k or an instance of a subclass of k 98 inline bool is_a(Klass* k) const; 99 100 // Returns the actual oop size of the object 101 inline int size(); 102 103 // Sometimes (for complicated concurrency-related reasons), it is useful 104 // to be able to figure out the size of an object knowing its klass. 105 inline int size_given_klass(Klass* klass); 106 107 // type test operations (inlined in oop.inline.hpp) 108 inline bool is_instance() const; 109 inline bool is_array() const; 110 inline bool is_objArray() const; 111 inline bool is_typeArray() const; 112 113 // type test operations that don't require inclusion of oop.inline.hpp. 114 bool is_instance_noinline() const; 115 bool is_array_noinline() const; 116 bool is_objArray_noinline() const; 117 bool is_typeArray_noinline() const; 118 119 protected: 120 inline oop as_oop() const { return const_cast<oopDesc*>(this); } 121 122 public: 123 // field addresses in oop 124 inline void* field_addr(int offset) const; 125 inline void* field_addr_raw(int offset) const; 126 127 // Need this as public for garbage collection. 128 template <class T> inline T* obj_field_addr_raw(int offset) const; 129 130 inline static bool is_null(oop obj) { return obj == NULL; } 131 inline static bool is_null(narrowOop obj) { return obj == 0; } 132 133 // Standard compare function returns negative value if o1 < o2 134 // 0 if o1 == o2 135 // positive value if o1 > o2 136 inline static int compare(oop o1, oop o2) { 137 void* o1_addr = (void*)o1; 138 void* o2_addr = (void*)o2; 139 if (o1_addr < o2_addr) { 140 return -1; 141 } else if (o1_addr > o2_addr) { 142 return 1; 143 } else { 144 return 0; 145 } 146 } 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 // Access to fields in a instanceOop through these methods. 184 template <DecoratorSet decorator> 185 oop obj_field_access(int offset) const; 186 oop obj_field(int offset) const; 187 void obj_field_put(int offset, oop value); 188 void obj_field_put_raw(int offset, oop value); 189 void obj_field_put_volatile(int offset, oop value); 190 191 Metadata* metadata_field(int offset) const; 192 void metadata_field_put(int offset, Metadata* value); 193 194 Metadata* metadata_field_acquire(int offset) const; 195 void release_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 and guarantees 278 static bool is_oop(oop obj, bool ignore_mark_word = false); 279 static bool is_oop_or_null(oop obj, bool ignore_mark_word = false); 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 // Forward pointer operations for scavenge 288 inline bool is_forwarded() const; 289 290 inline void forward_to(oop p); 291 inline bool cas_forward_to(oop p, markOop compare); 292 293 #if INCLUDE_ALL_GCS 294 // Like "forward_to", but inserts the forwarding pointer atomically. 295 // Exactly one thread succeeds in inserting the forwarding pointer, and 296 // this call returns "NULL" for that thread; any other thread has the 297 // value of the forwarding pointer returned and does not modify "this". 298 inline oop forward_to_atomic(oop p); 299 #endif // INCLUDE_ALL_GCS 300 301 inline oop forwardee() const; 302 303 // Age of object during scavenge 304 inline uint age() const; 305 inline void incr_age(); 306 307 // mark-sweep support 308 void follow_body(int begin, int end); 309 310 // Garbage Collection support 311 312 #if INCLUDE_ALL_GCS 313 // Parallel Compact 314 inline void pc_follow_contents(ParCompactionManager* cm); 315 inline void pc_update_contents(ParCompactionManager* cm); 316 // Parallel Scavenge 317 inline void ps_push_contents(PSPromotionManager* pm); 318 #endif 319 320 321 // iterators, returns size of object 322 #define OOP_ITERATE_DECL(OopClosureType, nv_suffix) \ 323 inline void oop_iterate(OopClosureType* blk); \ 324 inline void oop_iterate(OopClosureType* blk, MemRegion mr); // Only in mr. 325 326 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_DECL) 327 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_DECL) 328 329 #define OOP_ITERATE_SIZE_DECL(OopClosureType, nv_suffix) \ 330 inline int oop_iterate_size(OopClosureType* blk); \ 331 inline int oop_iterate_size(OopClosureType* blk, MemRegion mr); // Only in mr. 332 333 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_SIZE_DECL) 334 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_SIZE_DECL) 335 336 337 #if INCLUDE_ALL_GCS 338 339 #define OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \ 340 inline void oop_iterate_backwards(OopClosureType* blk); 341 342 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_BACKWARDS_DECL) 343 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_BACKWARDS_DECL) 344 345 #endif // INCLUDE_ALL_GCS 346 347 inline int oop_iterate_no_header(OopClosure* bk); 348 inline int oop_iterate_no_header(OopClosure* bk, MemRegion mr); 349 350 // identity hash; returns the identity hash key (computes it if necessary) 351 // NOTE with the introduction of UseBiasedLocking that identity_hash() might reach a 352 // safepoint if called on a biased object. Calling code must be aware of that. 353 inline intptr_t identity_hash(); 354 intptr_t slow_identity_hash(); 355 356 // Alternate hashing code if string table is rehashed 357 unsigned int new_hash(juint seed); 358 359 // marks are forwarded to stack when object is locked 360 inline bool has_displaced_mark() const; 361 inline markOop displaced_mark() const; 362 inline void set_displaced_mark(markOop m); 363 364 static bool has_klass_gap(); 365 366 // for code generation 367 static int mark_offset_in_bytes() { return offset_of(oopDesc, _mark); } 368 static int klass_offset_in_bytes() { return offset_of(oopDesc, _metadata._klass); } 369 static int klass_gap_offset_in_bytes() { 370 assert(has_klass_gap(), "only applicable to compressed klass pointers"); 371 return klass_offset_in_bytes() + sizeof(narrowKlass); 372 } 373 374 static bool is_archive_object(oop p) NOT_CDS_JAVA_HEAP_RETURN_(false); 375 }; 376 377 #endif // SHARE_VM_OOPS_OOP_HPP