1 /* 2 * Copyright (c) 1997, 2017, 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 public: 65 markOop mark() const { return _mark; } 66 markOop* mark_addr() const { return (markOop*) &_mark; } 67 68 void set_mark(volatile markOop m) { _mark = m; } 69 70 inline void release_set_mark(markOop m); 71 inline markOop cas_set_mark(markOop new_mark, markOop old_mark); 72 73 // Used only to re-initialize the mark word (e.g., of promoted 74 // objects during a GC) -- requires a valid klass pointer 75 inline void init_mark(); 76 77 inline Klass* klass() const; 78 inline Klass* klass_or_null() const volatile; 79 inline Klass* klass_or_null_acquire() const volatile; 80 inline Klass** klass_addr(); 81 inline narrowKlass* compressed_klass_addr(); 82 83 inline void set_klass(Klass* k); 84 inline void release_set_klass(Klass* k); 85 86 // For klass field compression 87 inline int klass_gap() const; 88 inline void set_klass_gap(int z); 89 // For when the klass pointer is being used as a linked list "next" field. 90 inline void set_klass_to_list_ptr(oop k); 91 inline oop list_ptr_from_klass(); 92 93 // size of object header, aligned to platform wordSize 94 static int header_size() { return sizeof(oopDesc)/HeapWordSize; } 95 96 // Returns whether this is an instance of k or an instance of a subclass of k 97 inline bool is_a(Klass* k) const; 98 99 // Returns the actual oop size of the object 100 inline int size(); 101 102 // Sometimes (for complicated concurrency-related reasons), it is useful 103 // to be able to figure out the size of an object knowing its klass. 104 inline int size_given_klass(Klass* klass); 105 106 // type test operations (inlined in oop.inline.hpp) 107 inline bool is_instance() const; 108 inline bool is_array() const; 109 inline bool is_objArray() const; 110 inline bool is_typeArray() const; 111 112 // type test operations that don't require inclusion of oop.inline.hpp. 113 bool is_instance_noinline() const; 114 bool is_array_noinline() const; 115 bool is_objArray_noinline() const; 116 bool is_typeArray_noinline() const; 117 118 protected: 119 inline oop as_oop() const { return const_cast<oopDesc*>(this); } 120 121 private: 122 // field addresses in oop 123 inline void* field_base(int offset) const; 124 125 inline jbyte* byte_field_addr(int offset) const; 126 inline jchar* char_field_addr(int offset) const; 127 inline jboolean* bool_field_addr(int offset) const; 128 inline jint* int_field_addr(int offset) const; 129 inline jshort* short_field_addr(int offset) const; 130 inline jlong* long_field_addr(int offset) const; 131 inline jfloat* float_field_addr(int offset) const; 132 inline jdouble* double_field_addr(int offset) const; 133 inline Metadata** metadata_field_addr(int offset) const; 134 135 public: 136 // Need this as public for garbage collection. 137 template <class T> inline T* obj_field_addr(int offset) const; 138 139 // Needed for javaClasses 140 inline address* address_field_addr(int offset) const; 141 142 inline static bool is_null(oop obj) { return obj == NULL; } 143 inline static bool is_null(narrowOop obj) { return obj == 0; } 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 inline oop decode_heap_oop_not_null(oop v) { return v; } 149 static inline oop decode_heap_oop_not_null(narrowOop v); 150 static inline oop decode_heap_oop(oop v) { return v; } 151 static inline 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 inline narrowOop encode_heap_oop_not_null(oop v); 157 static inline narrowOop encode_heap_oop(oop v); 158 159 // Load an oop out of the Java heap as is without decoding. 160 // Called by GC to check for null before decoding. 161 static inline narrowOop load_heap_oop(narrowOop* p); 162 static inline oop load_heap_oop(oop* p); 163 164 // Load an oop out of Java heap and decode it to an uncompressed oop. 165 static inline oop load_decode_heap_oop_not_null(narrowOop* p); 166 static inline oop load_decode_heap_oop_not_null(oop* p); 167 static inline oop load_decode_heap_oop(narrowOop* p); 168 static inline oop load_decode_heap_oop(oop* p); 169 170 // Store already encoded heap oop into the heap. 171 static inline void store_heap_oop(narrowOop* p, narrowOop v); 172 static inline void store_heap_oop(oop* p, oop v); 173 174 // Encode oop if UseCompressedOops and store into the heap. 175 static inline void encode_store_heap_oop_not_null(narrowOop* p, oop v); 176 static inline void encode_store_heap_oop_not_null(oop* p, oop v); 177 static inline void encode_store_heap_oop(narrowOop* p, oop v); 178 static inline void encode_store_heap_oop(oop* p, oop v); 179 180 // Access to fields in a instanceOop through these methods. 181 oop obj_field(int offset) const; 182 void obj_field_put(int offset, oop value); 183 void obj_field_put_raw(int offset, oop value); 184 void obj_field_put_volatile(int offset, oop value); 185 186 Metadata* metadata_field(int offset) const; 187 void metadata_field_put(int offset, Metadata* value); 188 189 Metadata* metadata_field_acquire(int offset) const; 190 void release_metadata_field_put(int offset, Metadata* value); 191 192 jbyte byte_field(int offset) const; 193 void byte_field_put(int offset, jbyte contents); 194 195 jchar char_field(int offset) const; 196 void char_field_put(int offset, jchar contents); 197 198 jboolean bool_field(int offset) const; 199 void bool_field_put(int offset, jboolean contents); 200 201 jint int_field(int offset) const; 202 void int_field_put(int offset, jint contents); 203 204 jshort short_field(int offset) const; 205 void short_field_put(int offset, jshort contents); 206 207 jlong long_field(int offset) const; 208 void long_field_put(int offset, jlong contents); 209 210 jfloat float_field(int offset) const; 211 void float_field_put(int offset, jfloat contents); 212 213 jdouble double_field(int offset) const; 214 void double_field_put(int offset, jdouble contents); 215 216 address address_field(int offset) const; 217 void address_field_put(int offset, address contents); 218 219 oop obj_field_acquire(int offset) const; 220 void release_obj_field_put(int offset, oop value); 221 222 jbyte byte_field_acquire(int offset) const; 223 void release_byte_field_put(int offset, jbyte contents); 224 225 jchar char_field_acquire(int offset) const; 226 void release_char_field_put(int offset, jchar contents); 227 228 jboolean bool_field_acquire(int offset) const; 229 void release_bool_field_put(int offset, jboolean contents); 230 231 jint int_field_acquire(int offset) const; 232 void release_int_field_put(int offset, jint contents); 233 234 jshort short_field_acquire(int offset) const; 235 void release_short_field_put(int offset, jshort contents); 236 237 jlong long_field_acquire(int offset) const; 238 void release_long_field_put(int offset, jlong contents); 239 240 jfloat float_field_acquire(int offset) const; 241 void release_float_field_put(int offset, jfloat contents); 242 243 jdouble double_field_acquire(int offset) const; 244 void release_double_field_put(int offset, jdouble contents); 245 246 address address_field_acquire(int offset) const; 247 void release_address_field_put(int offset, address contents); 248 249 // printing functions for VM debugging 250 void print_on(outputStream* st) const; // First level print 251 void print_value_on(outputStream* st) const; // Second level print. 252 void print_address_on(outputStream* st) const; // Address printing 253 254 // printing on default output stream 255 void print(); 256 void print_value(); 257 void print_address(); 258 259 // return the print strings 260 char* print_string(); 261 char* print_value_string(); 262 263 // verification operations 264 void verify_on(outputStream* st); 265 void verify(); 266 267 // locking operations 268 inline bool is_locked() const; 269 inline bool is_unlocked() const; 270 inline bool has_bias_pattern() const; 271 272 // asserts and guarantees 273 static bool is_oop(oop obj, bool ignore_mark_word = false); 274 static bool is_oop_or_null(oop obj, bool ignore_mark_word = false); 275 #ifndef PRODUCT 276 inline bool is_unlocked_oop() const; 277 #endif 278 279 // garbage collection 280 inline bool is_gc_marked() const; 281 282 inline bool is_scavengable() const; 283 284 // Forward pointer operations for scavenge 285 inline bool is_forwarded() const; 286 287 inline void forward_to(oop p); 288 inline bool cas_forward_to(oop p, markOop compare); 289 290 #if INCLUDE_ALL_GCS 291 // Like "forward_to", but inserts the forwarding pointer atomically. 292 // Exactly one thread succeeds in inserting the forwarding pointer, and 293 // this call returns "NULL" for that thread; any other thread has the 294 // value of the forwarding pointer returned and does not modify "this". 295 inline oop forward_to_atomic(oop p); 296 #endif // INCLUDE_ALL_GCS 297 298 inline oop forwardee() const; 299 300 // Age of object during scavenge 301 inline uint age() const; 302 inline void incr_age(); 303 304 // mark-sweep support 305 void follow_body(int begin, int end); 306 307 // Garbage Collection support 308 309 #if INCLUDE_ALL_GCS 310 // Parallel Compact 311 inline void pc_follow_contents(ParCompactionManager* cm); 312 inline void pc_update_contents(ParCompactionManager* cm); 313 // Parallel Scavenge 314 inline void ps_push_contents(PSPromotionManager* pm); 315 #endif 316 317 318 // iterators, returns size of object 319 #define OOP_ITERATE_DECL(OopClosureType, nv_suffix) \ 320 inline void oop_iterate(OopClosureType* blk); \ 321 inline void oop_iterate(OopClosureType* blk, MemRegion mr); // Only in mr. 322 323 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_DECL) 324 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_DECL) 325 326 #define OOP_ITERATE_SIZE_DECL(OopClosureType, nv_suffix) \ 327 inline int oop_iterate_size(OopClosureType* blk); \ 328 inline int oop_iterate_size(OopClosureType* blk, MemRegion mr); // Only in mr. 329 330 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_SIZE_DECL) 331 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_SIZE_DECL) 332 333 334 #if INCLUDE_ALL_GCS 335 336 #define OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \ 337 inline void oop_iterate_backwards(OopClosureType* blk); 338 339 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_BACKWARDS_DECL) 340 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_BACKWARDS_DECL) 341 342 #endif // INCLUDE_ALL_GCS 343 344 inline int oop_iterate_no_header(OopClosure* bk); 345 inline int oop_iterate_no_header(OopClosure* bk, MemRegion mr); 346 347 // identity hash; returns the identity hash key (computes it if necessary) 348 // NOTE with the introduction of UseBiasedLocking that identity_hash() might reach a 349 // safepoint if called on a biased object. Calling code must be aware of that. 350 inline intptr_t identity_hash(); 351 intptr_t slow_identity_hash(); 352 353 // Alternate hashing code if string table is rehashed 354 unsigned int new_hash(juint seed); 355 356 // marks are forwarded to stack when object is locked 357 inline bool has_displaced_mark() const; 358 inline markOop displaced_mark() const; 359 inline void set_displaced_mark(markOop m); 360 361 static bool has_klass_gap(); 362 363 // for code generation 364 static int mark_offset_in_bytes() { return offset_of(oopDesc, _mark); } 365 static int klass_offset_in_bytes() { return offset_of(oopDesc, _metadata._klass); } 366 static int klass_gap_offset_in_bytes() { 367 assert(has_klass_gap(), "only applicable to compressed klass pointers"); 368 return klass_offset_in_bytes() + sizeof(narrowKlass); 369 } 370 371 static bool is_archive_object(oop p) NOT_CDS_JAVA_HEAP_RETURN_(false); 372 }; 373 374 #endif // SHARE_VM_OOPS_OOP_HPP