1 /* 2 * Copyright (c) 1997, 2019, 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_OOPS_OOP_HPP 26 #define SHARE_OOPS_OOP_HPP 27 28 #include "memory/iterator.hpp" 29 #include "memory/memRegion.hpp" 30 #include "oops/access.hpp" 31 #include "oops/markWord.hpp" 32 #include "oops/metadata.hpp" 33 #include "runtime/atomic.hpp" 34 #include "utilities/macros.hpp" 35 36 // oopDesc is the top baseclass for objects classes. The {name}Desc classes describe 37 // the format of Java objects so the fields can be accessed from C++. 38 // oopDesc is abstract. 39 // (see oopHierarchy for complete oop class hierarchy) 40 // 41 // no virtual functions allowed 42 43 extern bool always_do_update_barrier; 44 45 // Forward declarations. 46 class OopClosure; 47 class ScanClosure; 48 class FastScanClosure; 49 class FilteringClosure; 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 markWord _mark; 60 union _metadata { 61 Klass* _klass; 62 narrowKlass _compressed_klass; 63 } _metadata; 64 65 public: 66 inline markWord mark() const; 67 inline markWord mark_raw() const; 68 inline markWord* mark_addr_raw() const; 69 70 inline void set_mark(volatile markWord m); 71 inline void set_mark_raw(volatile markWord m); 72 static inline void set_mark_raw(HeapWord* mem, markWord m); 73 74 inline void release_set_mark(markWord m); 75 inline markWord cas_set_mark(markWord new_mark, markWord old_mark); 76 inline markWord cas_set_mark_raw(markWord new_mark, markWord old_mark, atomic_memory_order order = memory_order_conservative); 77 78 // Used only to re-initialize the mark word (e.g., of promoted 79 // objects during a GC) -- requires a valid klass pointer 80 inline void init_mark(); 81 inline void init_mark_raw(); 82 83 inline Klass* klass() const; 84 inline Klass* klass_or_null() const volatile; 85 inline Klass* klass_or_null_acquire() const volatile; 86 static inline Klass** klass_addr(HeapWord* mem); 87 static inline narrowKlass* compressed_klass_addr(HeapWord* mem); 88 inline Klass** klass_addr(); 89 inline narrowKlass* compressed_klass_addr(); 90 91 inline void set_klass(Klass* k); 92 static inline void release_set_klass(HeapWord* mem, Klass* klass); 93 94 // For klass field compression 95 inline int klass_gap() const; 96 inline void set_klass_gap(int z); 97 static inline void set_klass_gap(HeapWord* mem, int z); 98 // For when the klass pointer is being used as a linked list "next" field. 99 inline void set_klass_to_list_ptr(oop k); 100 inline oop list_ptr_from_klass(); 101 102 // size of object header, aligned to platform wordSize 103 static int header_size() { return sizeof(oopDesc)/HeapWordSize; } 104 105 // Returns whether this is an instance of k or an instance of a subclass of k 106 inline bool is_a(Klass* k) const; 107 108 // Returns the actual oop size of the object 109 inline int size(); 110 111 // Sometimes (for complicated concurrency-related reasons), it is useful 112 // to be able to figure out the size of an object knowing its klass. 113 inline int size_given_klass(Klass* klass); 114 115 // type test operations (inlined in oop.inline.hpp) 116 inline bool is_instance() const; 117 inline bool is_array() const; 118 inline bool is_objArray() const; 119 inline bool is_typeArray() const; 120 121 // type test operations that don't require inclusion of oop.inline.hpp. 122 bool is_instance_noinline() const; 123 bool is_array_noinline() const; 124 bool is_objArray_noinline() const; 125 bool is_typeArray_noinline() const; 126 127 protected: 128 inline oop as_oop() const { return const_cast<oopDesc*>(this); } 129 130 public: 131 // field addresses in oop 132 inline void* field_addr(int offset) const; 133 inline void* field_addr_raw(int offset) const; 134 135 // Need this as public for garbage collection. 136 template <class T> inline T* obj_field_addr_raw(int offset) const; 137 138 template <typename T> inline size_t field_offset(T* p) const; 139 140 // Standard compare function returns negative value if o1 < o2 141 // 0 if o1 == o2 142 // positive value if o1 > o2 143 inline static int compare(oop o1, oop o2) { 144 void* o1_addr = (void*)o1; 145 void* o2_addr = (void*)o2; 146 if (o1_addr < o2_addr) { 147 return -1; 148 } else if (o1_addr > o2_addr) { 149 return 1; 150 } else { 151 return 0; 152 } 153 } 154 155 inline static bool equals(oop o1, oop o2) { return Access<>::equals(o1, o2); } 156 157 inline static bool equals_raw(oop o1, oop o2) { return RawAccess<>::equals(o1, o2); } 158 159 // Access to fields in a instanceOop through these methods. 160 template <DecoratorSet decorator> 161 oop obj_field_access(int offset) const; 162 oop obj_field(int offset) const; 163 void obj_field_put(int offset, oop value); 164 void obj_field_put_raw(int offset, oop value); 165 void obj_field_put_volatile(int offset, oop value); 166 167 Metadata* metadata_field(int offset) const; 168 Metadata* metadata_field_raw(int offset) const; 169 void metadata_field_put(int offset, Metadata* value); 170 171 Metadata* metadata_field_acquire(int offset) const; 172 void release_metadata_field_put(int offset, Metadata* value); 173 174 jbyte byte_field(int offset) const; 175 void byte_field_put(int offset, jbyte contents); 176 177 jchar char_field(int offset) const; 178 void char_field_put(int offset, jchar contents); 179 180 jboolean bool_field(int offset) const; 181 void bool_field_put(int offset, jboolean contents); 182 183 jint int_field(int offset) const; 184 jint int_field_raw(int offset) const; 185 void int_field_put(int offset, jint contents); 186 187 jshort short_field(int offset) const; 188 void short_field_put(int offset, jshort contents); 189 190 jlong long_field(int offset) const; 191 void long_field_put(int offset, jlong contents); 192 193 jfloat float_field(int offset) const; 194 void float_field_put(int offset, jfloat contents); 195 196 jdouble double_field(int offset) const; 197 void double_field_put(int offset, jdouble contents); 198 199 address address_field(int offset) const; 200 void address_field_put(int offset, address contents); 201 202 oop obj_field_acquire(int offset) const; 203 void release_obj_field_put(int offset, oop value); 204 205 jbyte byte_field_acquire(int offset) const; 206 void release_byte_field_put(int offset, jbyte contents); 207 208 jchar char_field_acquire(int offset) const; 209 void release_char_field_put(int offset, jchar contents); 210 211 jboolean bool_field_acquire(int offset) const; 212 void release_bool_field_put(int offset, jboolean contents); 213 214 jint int_field_acquire(int offset) const; 215 void release_int_field_put(int offset, jint contents); 216 217 jshort short_field_acquire(int offset) const; 218 void release_short_field_put(int offset, jshort contents); 219 220 jlong long_field_acquire(int offset) const; 221 void release_long_field_put(int offset, jlong contents); 222 223 jfloat float_field_acquire(int offset) const; 224 void release_float_field_put(int offset, jfloat contents); 225 226 jdouble double_field_acquire(int offset) const; 227 void release_double_field_put(int offset, jdouble contents); 228 229 address address_field_acquire(int offset) const; 230 void release_address_field_put(int offset, address contents); 231 232 // printing functions for VM debugging 233 void print_on(outputStream* st) const; // First level print 234 void print_value_on(outputStream* st) const; // Second level print. 235 void print_address_on(outputStream* st) const; // Address printing 236 237 // printing on default output stream 238 void print(); 239 void print_value(); 240 void print_address(); 241 242 // return the print strings 243 char* print_string(); 244 char* print_value_string(); 245 246 // verification operations 247 static void verify_on(outputStream* st, oopDesc* oop_desc); 248 static void verify(oopDesc* oopDesc); 249 250 // locking operations 251 inline bool is_locked() const; 252 inline bool is_unlocked() const; 253 inline bool has_bias_pattern() const; 254 inline bool has_bias_pattern_raw() const; 255 256 // asserts and guarantees 257 static bool is_oop(oop obj, bool ignore_mark_word = false); 258 static bool is_oop_or_null(oop obj, bool ignore_mark_word = false); 259 #ifndef PRODUCT 260 static bool is_archived_object(oop p) NOT_CDS_JAVA_HEAP_RETURN_(false); 261 #endif 262 263 // garbage collection 264 inline bool is_gc_marked() const; 265 266 // Forward pointer operations for scavenge 267 inline bool is_forwarded() const; 268 269 inline void forward_to(oop p); 270 inline bool cas_forward_to(oop p, markWord compare, atomic_memory_order order = memory_order_conservative); 271 272 // Like "forward_to", but inserts the forwarding pointer atomically. 273 // Exactly one thread succeeds in inserting the forwarding pointer, and 274 // this call returns "NULL" for that thread; any other thread has the 275 // value of the forwarding pointer returned and does not modify "this". 276 inline oop forward_to_atomic(oop p, markWord compare, atomic_memory_order order = memory_order_conservative); 277 278 inline oop forwardee() const; 279 inline oop forwardee_acquire() const; 280 281 // Age of object during scavenge 282 inline uint age() const; 283 inline void incr_age(); 284 285 // mark-sweep support 286 void follow_body(int begin, int end); 287 288 template <typename OopClosureType> 289 inline void oop_iterate(OopClosureType* cl); 290 291 template <typename OopClosureType> 292 inline void oop_iterate(OopClosureType* cl, MemRegion mr); 293 294 template <typename OopClosureType> 295 inline int oop_iterate_size(OopClosureType* cl); 296 297 template <typename OopClosureType> 298 inline int oop_iterate_size(OopClosureType* cl, MemRegion mr); 299 300 template <typename OopClosureType> 301 inline void oop_iterate_backwards(OopClosureType* cl); 302 303 inline static bool is_instanceof_or_null(oop obj, Klass* klass); 304 305 // identity hash; returns the identity hash key (computes it if necessary) 306 // NOTE with the introduction of UseBiasedLocking that identity_hash() might reach a 307 // safepoint if called on a biased object. Calling code must be aware of that. 308 inline intptr_t identity_hash(); 309 intptr_t slow_identity_hash(); 310 311 // marks are forwarded to stack when object is locked 312 inline bool has_displaced_mark_raw() const; 313 inline markWord displaced_mark_raw() const; 314 inline void set_displaced_mark_raw(markWord m); 315 316 static bool has_klass_gap(); 317 318 // for code generation 319 static int mark_offset_in_bytes() { return offset_of(oopDesc, _mark); } 320 static int klass_offset_in_bytes() { return offset_of(oopDesc, _metadata._klass); } 321 static int klass_gap_offset_in_bytes() { 322 assert(has_klass_gap(), "only applicable to compressed klass pointers"); 323 return klass_offset_in_bytes() + sizeof(narrowKlass); 324 } 325 326 // for error reporting 327 static void* load_klass_raw(oop obj); 328 static void* load_oop_raw(oop obj, int offset); 329 static bool is_valid(oop obj); 330 static oop oop_or_null(address addr); 331 }; 332 333 #endif // SHARE_OOPS_OOP_HPP