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
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.
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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 "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 { return _mark; }
67 markOop* mark_addr() const { return (markOop*) &_mark; }
68
69 void set_mark(volatile markOop m) { _mark = 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 // Standard compare function returns negative value if o1 < o2
131 // 0 if o1 == o2
132 // positive value if o1 > o2
133 inline static int compare(oop o1, oop o2) {
134 void* o1_addr = (void*)o1;
135 void* o2_addr = (void*)o2;
136 if (o1_addr < o2_addr) {
137 return -1;
138 } else if (o1_addr > o2_addr) {
139 return 1;
140 } else {
141 return 0;
142 }
143 }
144
145 // Access to fields in a instanceOop through these methods.
146 template <DecoratorSet decorator>
147 oop obj_field_access(int offset) const;
148 oop obj_field(int offset) const;
149 void obj_field_put(int offset, oop value);
150 void obj_field_put_raw(int offset, oop value);
151 void obj_field_put_volatile(int offset, oop value);
152
153 Metadata* metadata_field(int offset) const;
154 void metadata_field_put(int offset, Metadata* value);
155
156 Metadata* metadata_field_acquire(int offset) const;
157 void release_metadata_field_put(int offset, Metadata* value);
158
159 jbyte byte_field(int offset) const;
160 void byte_field_put(int offset, jbyte contents);
161
162 jchar char_field(int offset) const;
163 void char_field_put(int offset, jchar contents);
164
165 jboolean bool_field(int offset) const;
166 void bool_field_put(int offset, jboolean contents);
167
168 jint int_field(int offset) const;
169 void int_field_put(int offset, jint contents);
170
171 jshort short_field(int offset) const;
172 void short_field_put(int offset, jshort contents);
173
174 jlong long_field(int offset) const;
175 void long_field_put(int offset, jlong contents);
176
177 jfloat float_field(int offset) const;
178 void float_field_put(int offset, jfloat contents);
179
180 jdouble double_field(int offset) const;
181 void double_field_put(int offset, jdouble contents);
182
183 address address_field(int offset) const;
184 void address_field_put(int offset, address contents);
185
186 oop obj_field_acquire(int offset) const;
187 void release_obj_field_put(int offset, oop value);
188
189 jbyte byte_field_acquire(int offset) const;
190 void release_byte_field_put(int offset, jbyte contents);
191
192 jchar char_field_acquire(int offset) const;
193 void release_char_field_put(int offset, jchar contents);
194
195 jboolean bool_field_acquire(int offset) const;
196 void release_bool_field_put(int offset, jboolean contents);
197
198 jint int_field_acquire(int offset) const;
199 void release_int_field_put(int offset, jint contents);
200
201 jshort short_field_acquire(int offset) const;
202 void release_short_field_put(int offset, jshort contents);
203
204 jlong long_field_acquire(int offset) const;
205 void release_long_field_put(int offset, jlong contents);
206
207 jfloat float_field_acquire(int offset) const;
208 void release_float_field_put(int offset, jfloat contents);
209
210 jdouble double_field_acquire(int offset) const;
211 void release_double_field_put(int offset, jdouble contents);
212
213 address address_field_acquire(int offset) const;
214 void release_address_field_put(int offset, address contents);
215
216 // printing functions for VM debugging
217 void print_on(outputStream* st) const; // First level print
218 void print_value_on(outputStream* st) const; // Second level print.
219 void print_address_on(outputStream* st) const; // Address printing
220
221 // printing on default output stream
222 void print();
223 void print_value();
224 void print_address();
225
226 // return the print strings
227 char* print_string();
228 char* print_value_string();
229
230 // verification operations
231 void verify_on(outputStream* st);
232 void verify();
233
234 // locking operations
235 inline bool is_locked() const;
236 inline bool is_unlocked() const;
237 inline bool has_bias_pattern() const;
238
239 // asserts and guarantees
240 static bool is_oop(oop obj, bool ignore_mark_word = false);
241 static bool is_oop_or_null(oop obj, bool ignore_mark_word = false);
242 #ifndef PRODUCT
243 inline bool is_unlocked_oop() const;
244 #endif
245
246 // garbage collection
247 inline bool is_gc_marked() const;
248
249 // Forward pointer operations for scavenge
250 inline bool is_forwarded() const;
251
252 inline void forward_to(oop p);
253 inline bool cas_forward_to(oop p, markOop compare);
254
255 #if INCLUDE_ALL_GCS
256 // Like "forward_to", but inserts the forwarding pointer atomically.
257 // Exactly one thread succeeds in inserting the forwarding pointer, and
258 // this call returns "NULL" for that thread; any other thread has the
259 // value of the forwarding pointer returned and does not modify "this".
260 inline oop forward_to_atomic(oop p);
261 #endif // INCLUDE_ALL_GCS
262
263 inline oop forwardee() const;
264
265 // Age of object during scavenge
266 inline uint age() const;
267 inline void incr_age();
268
269 // mark-sweep support
270 void follow_body(int begin, int end);
271
272 // Garbage Collection support
273
274 #if INCLUDE_ALL_GCS
275 // Parallel Compact
276 inline void pc_follow_contents(ParCompactionManager* cm);
277 inline void pc_update_contents(ParCompactionManager* cm);
278 // Parallel Scavenge
279 inline void ps_push_contents(PSPromotionManager* pm);
280 #endif
281
282
283 // iterators, returns size of object
284 #define OOP_ITERATE_DECL(OopClosureType, nv_suffix) \
285 inline void oop_iterate(OopClosureType* blk); \
286 inline void oop_iterate(OopClosureType* blk, MemRegion mr); // Only in mr.
287
288 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_DECL)
289 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_DECL)
290
291 #define OOP_ITERATE_SIZE_DECL(OopClosureType, nv_suffix) \
292 inline int oop_iterate_size(OopClosureType* blk); \
293 inline int oop_iterate_size(OopClosureType* blk, MemRegion mr); // Only in mr.
294
295 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_SIZE_DECL)
296 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_SIZE_DECL)
297
298
299 #if INCLUDE_ALL_GCS
300
301 #define OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \
302 inline void oop_iterate_backwards(OopClosureType* blk);
303
304 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_BACKWARDS_DECL)
305 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_BACKWARDS_DECL)
306
307 #endif // INCLUDE_ALL_GCS
308
309 inline int oop_iterate_no_header(OopClosure* bk);
310 inline int oop_iterate_no_header(OopClosure* bk, MemRegion mr);
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() const;
325 inline markOop displaced_mark() const;
326 inline void set_displaced_mark(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 static bool is_archive_object(oop p) NOT_CDS_JAVA_HEAP_RETURN_(false);
339 };
340
341 #endif // SHARE_VM_OOPS_OOP_HPP