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.
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5 * This code is free software; you can redistribute it and/or modify it
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7 * published by the Free Software Foundation.
8 *
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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.
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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23 */
24
25 #ifndef SHARE_VM_OOPS_OOP_HPP
26 #define SHARE_VM_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 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 inline markOop mark() const;
67 inline markOop mark_raw() const;
68 inline markOop* mark_addr_raw() const;
69
70 inline void set_mark(volatile markOop m);
71 inline void set_mark_raw(volatile markOop m);
72 static inline void set_mark_raw(HeapWord* mem, markOop m);
73
74 inline void release_set_mark(markOop m);
75 inline markOop cas_set_mark(markOop new_mark, markOop old_mark);
76 inline markOop cas_set_mark_raw(markOop new_mark, markOop 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 // Access to fields in a instanceOop through these methods.
158 template <DecoratorSet decorator>
159 oop obj_field_access(int offset) const;
160 oop obj_field(int offset) const;
161 void obj_field_put(int offset, oop value);
162 void obj_field_put_raw(int offset, oop value);
163 void obj_field_put_volatile(int offset, oop value);
164
165 Metadata* metadata_field(int offset) const;
166 Metadata* metadata_field_raw(int offset) const;
167 void metadata_field_put(int offset, Metadata* value);
168
169 Metadata* metadata_field_acquire(int offset) const;
170 void release_metadata_field_put(int offset, Metadata* value);
171
172 jbyte byte_field(int offset) const;
173 void byte_field_put(int offset, jbyte contents);
174
175 jchar char_field(int offset) const;
176 void char_field_put(int offset, jchar contents);
177
178 jboolean bool_field(int offset) const;
179 void bool_field_put(int offset, jboolean contents);
180
181 jint int_field(int offset) const;
182 jint int_field_raw(int offset) const;
183 void int_field_put(int offset, jint contents);
184
185 jshort short_field(int offset) const;
186 void short_field_put(int offset, jshort contents);
187
188 jlong long_field(int offset) const;
189 void long_field_put(int offset, jlong contents);
190
191 jfloat float_field(int offset) const;
192 void float_field_put(int offset, jfloat contents);
193
194 jdouble double_field(int offset) const;
195 void double_field_put(int offset, jdouble contents);
196
197 address address_field(int offset) const;
198 void address_field_put(int offset, address contents);
199
200 oop obj_field_acquire(int offset) const;
201 void release_obj_field_put(int offset, oop value);
202
203 jbyte byte_field_acquire(int offset) const;
204 void release_byte_field_put(int offset, jbyte contents);
205
206 jchar char_field_acquire(int offset) const;
207 void release_char_field_put(int offset, jchar contents);
208
209 jboolean bool_field_acquire(int offset) const;
210 void release_bool_field_put(int offset, jboolean contents);
211
212 jint int_field_acquire(int offset) const;
213 void release_int_field_put(int offset, jint contents);
214
215 jshort short_field_acquire(int offset) const;
216 void release_short_field_put(int offset, jshort contents);
217
218 jlong long_field_acquire(int offset) const;
219 void release_long_field_put(int offset, jlong contents);
220
221 jfloat float_field_acquire(int offset) const;
222 void release_float_field_put(int offset, jfloat contents);
223
224 jdouble double_field_acquire(int offset) const;
225 void release_double_field_put(int offset, jdouble contents);
226
227 address address_field_acquire(int offset) const;
228 void release_address_field_put(int offset, address contents);
229
230 // printing functions for VM debugging
231 void print_on(outputStream* st) const; // First level print
232 void print_value_on(outputStream* st) const; // Second level print.
233 void print_address_on(outputStream* st) const; // Address printing
234
235 // printing on default output stream
236 void print();
237 void print_value();
238 void print_address();
239
240 // return the print strings
241 char* print_string();
242 char* print_value_string();
243
244 // verification operations
245 static void verify_on(outputStream* st, oopDesc* oop_desc);
246 static void verify(oopDesc* oopDesc);
247
248 // locking operations
249 inline bool is_locked() const;
250 inline bool is_unlocked() const;
251 inline bool has_bias_pattern() const;
252 inline bool has_bias_pattern_raw() const;
253
254 // asserts and guarantees
255 static bool is_oop(oop obj, bool ignore_mark_word = false);
256 static bool is_oop_or_null(oop obj, bool ignore_mark_word = false);
257 #ifndef PRODUCT
258 inline bool is_unlocked_oop() const;
259 static bool is_archive_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, 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 // Garbage Collection support
288
289 #if INCLUDE_PARALLELGC
290 // Parallel Compact
291 inline void pc_follow_contents(ParCompactionManager* cm);
292 inline void pc_update_contents(ParCompactionManager* cm);
293 // Parallel Scavenge
294 inline void ps_push_contents(PSPromotionManager* pm);
295 #endif
296
297 template <typename OopClosureType>
298 inline void oop_iterate(OopClosureType* cl);
299
300 template <typename OopClosureType>
301 inline void oop_iterate(OopClosureType* cl, MemRegion mr);
302
303 template <typename OopClosureType>
304 inline int oop_iterate_size(OopClosureType* cl);
305
306 template <typename OopClosureType>
307 inline int oop_iterate_size(OopClosureType* cl, MemRegion mr);
308
309 template <typename OopClosureType>
310 inline void oop_iterate_backwards(OopClosureType* cl);
311
312 inline static bool is_instanceof_or_null(oop obj, Klass* klass);
313
314 // identity hash; returns the identity hash key (computes it if necessary)
315 // NOTE with the introduction of UseBiasedLocking that identity_hash() might reach a
316 // safepoint if called on a biased object. Calling code must be aware of that.
317 inline intptr_t identity_hash();
318 intptr_t slow_identity_hash();
319
320 // Alternate hashing code if string table is rehashed
321 unsigned int new_hash(juint seed);
322
323 // marks are forwarded to stack when object is locked
324 inline bool has_displaced_mark_raw() const;
325 inline markOop displaced_mark_raw() const;
326 inline void set_displaced_mark_raw(markOop m);
327
328 static bool has_klass_gap();
329
330 // for code generation
331 static int mark_offset_in_bytes() { return offset_of(oopDesc, _mark); }
332 static int klass_offset_in_bytes() { return offset_of(oopDesc, _metadata._klass); }
333 static int klass_gap_offset_in_bytes() {
334 assert(has_klass_gap(), "only applicable to compressed klass pointers");
335 return klass_offset_in_bytes() + sizeof(narrowKlass);
336 }
337 };
338
339 #endif // SHARE_VM_OOPS_OOP_HPP