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/metadata.hpp" 32 #include "runtime/atomic.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 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 inline markOop mark() const; 66 inline markOop mark_raw() const; 67 inline markOop* mark_addr_raw() const; 68 69 inline void set_mark(volatile markOop m); 70 inline void set_mark_raw(volatile markOop m); 71 static inline void set_mark_raw(HeapWord* mem, markOop m); 72 73 inline void release_set_mark(markOop m); 74 inline markOop cas_set_mark(markOop new_mark, markOop old_mark); 75 inline markOop cas_set_mark_raw(markOop new_mark, markOop old_mark, atomic_memory_order order = memory_order_conservative); 76 77 // Used only to re-initialize the mark word (e.g., of promoted 78 // objects during a GC) -- requires a valid klass pointer 79 inline void init_mark(); 80 inline void init_mark_raw(); 81 82 inline Klass* klass() const; 83 inline Klass* klass_or_null() const volatile; 84 inline Klass* klass_or_null_acquire() const volatile; 85 static inline Klass** klass_addr(HeapWord* mem); 86 static inline narrowKlass* compressed_klass_addr(HeapWord* mem); 87 inline Klass** klass_addr(); 88 inline narrowKlass* compressed_klass_addr(); 89 90 inline void set_klass(Klass* k); 91 static inline void release_set_klass(HeapWord* mem, Klass* klass); 92 93 // For klass field compression 94 inline int klass_gap() const; 95 inline void set_klass_gap(int z); 96 static inline void set_klass_gap(HeapWord* mem, int z); 97 // For when the klass pointer is being used as a linked list "next" field. 98 inline void set_klass_to_list_ptr(oop k); 99 inline oop list_ptr_from_klass(); 100 101 // size of object header, aligned to platform wordSize header_size()102 static int header_size() { return sizeof(oopDesc)/HeapWordSize; } 103 104 // Returns whether this is an instance of k or an instance of a subclass of k 105 inline bool is_a(Klass* k) const; 106 107 // Returns the actual oop size of the object 108 inline int size(); 109 110 // Sometimes (for complicated concurrency-related reasons), it is useful 111 // to be able to figure out the size of an object knowing its klass. 112 inline int size_given_klass(Klass* klass); 113 114 // type test operations (inlined in oop.inline.hpp) 115 inline bool is_instance() const; 116 inline bool is_array() const; 117 inline bool is_objArray() const; 118 inline bool is_typeArray() const; 119 120 // type test operations that don't require inclusion of oop.inline.hpp. 121 bool is_instance_noinline() const; 122 bool is_array_noinline() const; 123 bool is_objArray_noinline() const; 124 bool is_typeArray_noinline() const; 125 126 protected: as_oop() const127 inline oop as_oop() const { return const_cast<oopDesc*>(this); } 128 129 public: 130 // field addresses in oop 131 inline void* field_addr(int offset) const; 132 inline void* field_addr_raw(int offset) const; 133 134 // Need this as public for garbage collection. 135 template <class T> inline T* obj_field_addr_raw(int offset) const; 136 137 template <typename T> inline size_t field_offset(T* p) const; 138 139 // Standard compare function returns negative value if o1 < o2 140 // 0 if o1 == o2 141 // positive value if o1 > o2 compare(oop o1,oop o2)142 inline static int compare(oop o1, oop o2) { 143 void* o1_addr = (void*)o1; 144 void* o2_addr = (void*)o2; 145 if (o1_addr < o2_addr) { 146 return -1; 147 } else if (o1_addr > o2_addr) { 148 return 1; 149 } else { 150 return 0; 151 } 152 } 153 equals(oop o1,oop o2)154 inline static bool equals(oop o1, oop o2) { return Access<>::equals(o1, o2); } 155 equals_raw(oop o1,oop o2)156 inline static bool equals_raw(oop o1, oop o2) { return RawAccess<>::equals(o1, o2); } 157 158 // Access to fields in a instanceOop through these methods. 159 template <DecoratorSet decorator> 160 oop obj_field_access(int offset) const; 161 oop obj_field(int offset) const; 162 void obj_field_put(int offset, oop value); 163 void obj_field_put_raw(int offset, oop value); 164 void obj_field_put_volatile(int offset, oop value); 165 166 Metadata* metadata_field(int offset) const; 167 Metadata* metadata_field_raw(int offset) const; 168 void metadata_field_put(int offset, Metadata* value); 169 170 Metadata* metadata_field_acquire(int offset) const; 171 void release_metadata_field_put(int offset, Metadata* value); 172 173 jbyte byte_field(int offset) const; 174 void byte_field_put(int offset, jbyte contents); 175 176 jchar char_field(int offset) const; 177 void char_field_put(int offset, jchar contents); 178 179 jboolean bool_field(int offset) const; 180 void bool_field_put(int offset, jboolean contents); 181 182 jint int_field(int offset) const; 183 jint int_field_raw(int offset) const; 184 void int_field_put(int offset, jint contents); 185 186 jshort short_field(int offset) const; 187 void short_field_put(int offset, jshort contents); 188 189 jlong long_field(int offset) const; 190 void long_field_put(int offset, jlong contents); 191 192 jfloat float_field(int offset) const; 193 void float_field_put(int offset, jfloat contents); 194 195 jdouble double_field(int offset) const; 196 void double_field_put(int offset, jdouble contents); 197 198 address address_field(int offset) const; 199 void address_field_put(int offset, address contents); 200 201 oop obj_field_acquire(int offset) const; 202 void release_obj_field_put(int offset, oop value); 203 204 jbyte byte_field_acquire(int offset) const; 205 void release_byte_field_put(int offset, jbyte contents); 206 207 jchar char_field_acquire(int offset) const; 208 void release_char_field_put(int offset, jchar contents); 209 210 jboolean bool_field_acquire(int offset) const; 211 void release_bool_field_put(int offset, jboolean contents); 212 213 jint int_field_acquire(int offset) const; 214 void release_int_field_put(int offset, jint contents); 215 216 jshort short_field_acquire(int offset) const; 217 void release_short_field_put(int offset, jshort contents); 218 219 jlong long_field_acquire(int offset) const; 220 void release_long_field_put(int offset, jlong contents); 221 222 jfloat float_field_acquire(int offset) const; 223 void release_float_field_put(int offset, jfloat contents); 224 225 jdouble double_field_acquire(int offset) const; 226 void release_double_field_put(int offset, jdouble contents); 227 228 address address_field_acquire(int offset) const; 229 void release_address_field_put(int offset, address contents); 230 231 // printing functions for VM debugging 232 void print_on(outputStream* st) const; // First level print 233 void print_value_on(outputStream* st) const; // Second level print. 234 void print_address_on(outputStream* st) const; // Address printing 235 236 // printing on default output stream 237 void print(); 238 void print_value(); 239 void print_address(); 240 241 // return the print strings 242 char* print_string(); 243 char* print_value_string(); 244 245 // verification operations 246 static void verify_on(outputStream* st, oopDesc* oop_desc); 247 static void verify(oopDesc* oopDesc); 248 249 // locking operations 250 inline bool is_locked() const; 251 inline bool is_unlocked() const; 252 inline bool has_bias_pattern() const; 253 inline bool has_bias_pattern_raw() const; 254 255 // asserts and guarantees 256 static bool is_oop(oop obj, bool ignore_mark_word = false); 257 static bool is_oop_or_null(oop obj, bool ignore_mark_word = false); 258 #ifndef PRODUCT 259 static bool is_archived_object(oop p) NOT_CDS_JAVA_HEAP_RETURN_(false); 260 #endif 261 262 // garbage collection 263 inline bool is_gc_marked() const; 264 265 // Forward pointer operations for scavenge 266 inline bool is_forwarded() const; 267 268 inline void forward_to(oop p); 269 inline bool cas_forward_to(oop p, markOop compare, atomic_memory_order order = memory_order_conservative); 270 271 // Like "forward_to", but inserts the forwarding pointer atomically. 272 // Exactly one thread succeeds in inserting the forwarding pointer, and 273 // this call returns "NULL" for that thread; any other thread has the 274 // value of the forwarding pointer returned and does not modify "this". 275 inline oop forward_to_atomic(oop p, markOop compare, atomic_memory_order order = memory_order_conservative); 276 277 inline oop forwardee() const; 278 inline oop forwardee_acquire() const; 279 280 // Age of object during scavenge 281 inline uint age() const; 282 inline void incr_age(); 283 284 // mark-sweep support 285 void follow_body(int begin, int end); 286 287 template <typename OopClosureType> 288 inline void oop_iterate(OopClosureType* cl); 289 290 template <typename OopClosureType> 291 inline void oop_iterate(OopClosureType* cl, MemRegion mr); 292 293 template <typename OopClosureType> 294 inline int oop_iterate_size(OopClosureType* cl); 295 296 template <typename OopClosureType> 297 inline int oop_iterate_size(OopClosureType* cl, MemRegion mr); 298 299 template <typename OopClosureType> 300 inline void oop_iterate_backwards(OopClosureType* cl); 301 302 inline static bool is_instanceof_or_null(oop obj, Klass* klass); 303 304 // identity hash; returns the identity hash key (computes it if necessary) 305 // NOTE with the introduction of UseBiasedLocking that identity_hash() might reach a 306 // safepoint if called on a biased object. Calling code must be aware of that. 307 inline intptr_t identity_hash(); 308 intptr_t slow_identity_hash(); 309 310 // marks are forwarded to stack when object is locked 311 inline bool has_displaced_mark_raw() const; 312 inline markOop displaced_mark_raw() const; 313 inline void set_displaced_mark_raw(markOop m); 314 315 static bool has_klass_gap(); 316 317 // for code generation mark_offset_in_bytes()318 static int mark_offset_in_bytes() { return offset_of(oopDesc, _mark); } klass_offset_in_bytes()319 static int klass_offset_in_bytes() { return offset_of(oopDesc, _metadata._klass); } klass_gap_offset_in_bytes()320 static int klass_gap_offset_in_bytes() { 321 assert(has_klass_gap(), "only applicable to compressed klass pointers"); 322 return klass_offset_in_bytes() + sizeof(narrowKlass); 323 } 324 325 // for error reporting 326 static void* load_klass_raw(oop obj); 327 static void* load_oop_raw(oop obj, int offset); 328 static bool is_valid(oop obj); 329 static oop oop_or_null(address addr); 330 }; 331 332 #endif // SHARE_OOPS_OOP_HPP 333