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.
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.
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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
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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 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
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);
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 inline Klass** klass_addr();
86 inline narrowKlass* compressed_klass_addr();
87
88 inline void set_klass(Klass* k);
89 inline void release_set_klass(Klass* k);
90
91 // For klass field compression
92 inline int klass_gap() const;
93 inline void set_klass_gap(int z);
94 // For when the klass pointer is being used as a linked list "next" field.
95 inline void set_klass_to_list_ptr(oop k);
96 inline oop list_ptr_from_klass();
97
98 // size of object header, aligned to platform wordSize
99 static int header_size() { return sizeof(oopDesc)/HeapWordSize; }
100
101 // Returns whether this is an instance of k or an instance of a subclass of k
102 inline bool is_a(Klass* k) const;
103
104 // Returns the actual oop size of the object
105 inline int size();
106
107 // Sometimes (for complicated concurrency-related reasons), it is useful
108 // to be able to figure out the size of an object knowing its klass.
109 inline int size_given_klass(Klass* klass);
110
111 // type test operations (inlined in oop.inline.hpp)
112 inline bool is_instance() const;
113 inline bool is_array() const;
114 inline bool is_objArray() const;
115 inline bool is_typeArray() const;
116
117 // type test operations that don't require inclusion of oop.inline.hpp.
118 bool is_instance_noinline() const;
119 bool is_array_noinline() const;
120 bool is_objArray_noinline() const;
121 bool is_typeArray_noinline() const;
122
123 protected:
124 inline oop as_oop() const { return const_cast<oopDesc*>(this); }
125
126 public:
127 // field addresses in oop
128 inline void* field_addr(int offset) const;
129 inline void* field_addr_raw(int offset) const;
130
131 // Need this as public for garbage collection.
132 template <class T> inline T* obj_field_addr_raw(int offset) const;
133
134 // Standard compare function returns negative value if o1 < o2
135 // 0 if o1 == o2
136 // positive value if o1 > o2
137 inline static int compare(oop o1, oop o2) {
138 void* o1_addr = (void*)o1;
139 void* o2_addr = (void*)o2;
140 if (o1_addr < o2_addr) {
141 return -1;
142 } else if (o1_addr > o2_addr) {
143 return 1;
144 } else {
145 return 0;
146 }
147 }
148
149 inline static bool equals(oop o1, oop o2) { return Access<>::equals(o1, o2); }
150
151 // Access to fields in a instanceOop through these methods.
152 template <DecoratorSet decorator>
153 oop obj_field_access(int offset) const;
154 oop obj_field(int offset) const;
155 void obj_field_put(int offset, oop value);
156 void obj_field_put_raw(int offset, oop value);
157 void obj_field_put_volatile(int offset, oop value);
158
159 Metadata* metadata_field(int offset) const;
160 void metadata_field_put(int offset, Metadata* value);
161
162 Metadata* metadata_field_acquire(int offset) const;
163 void release_metadata_field_put(int offset, Metadata* value);
164
165 jbyte byte_field(int offset) const;
166 void byte_field_put(int offset, jbyte contents);
167
168 jchar char_field(int offset) const;
169 void char_field_put(int offset, jchar contents);
170
171 jboolean bool_field(int offset) const;
172 void bool_field_put(int offset, jboolean contents);
173
174 jint int_field(int offset) const;
175 void int_field_put(int offset, jint contents);
176
177 jshort short_field(int offset) const;
178 void short_field_put(int offset, jshort contents);
179
180 jlong long_field(int offset) const;
181 void long_field_put(int offset, jlong contents);
182
183 jfloat float_field(int offset) const;
184 void float_field_put(int offset, jfloat contents);
185
186 jdouble double_field(int offset) const;
187 void double_field_put(int offset, jdouble contents);
188
189 address address_field(int offset) const;
190 void address_field_put(int offset, address contents);
191
192 oop obj_field_acquire(int offset) const;
193 void release_obj_field_put(int offset, oop value);
194
195 jbyte byte_field_acquire(int offset) const;
196 void release_byte_field_put(int offset, jbyte contents);
197
198 jchar char_field_acquire(int offset) const;
199 void release_char_field_put(int offset, jchar contents);
200
201 jboolean bool_field_acquire(int offset) const;
202 void release_bool_field_put(int offset, jboolean contents);
203
204 jint int_field_acquire(int offset) const;
205 void release_int_field_put(int offset, jint contents);
206
207 jshort short_field_acquire(int offset) const;
208 void release_short_field_put(int offset, jshort contents);
209
210 jlong long_field_acquire(int offset) const;
211 void release_long_field_put(int offset, jlong contents);
212
213 jfloat float_field_acquire(int offset) const;
214 void release_float_field_put(int offset, jfloat contents);
215
216 jdouble double_field_acquire(int offset) const;
217 void release_double_field_put(int offset, jdouble contents);
218
219 address address_field_acquire(int offset) const;
220 void release_address_field_put(int offset, address contents);
221
222 // printing functions for VM debugging
223 void print_on(outputStream* st) const; // First level print
224 void print_value_on(outputStream* st) const; // Second level print.
225 void print_address_on(outputStream* st) const; // Address printing
226
227 // printing on default output stream
228 void print();
229 void print_value();
230 void print_address();
231
232 // return the print strings
233 char* print_string();
234 char* print_value_string();
235
236 // verification operations
237 void verify_on(outputStream* st);
238 void verify();
239
240 // locking operations
241 inline bool is_locked() const;
242 inline bool is_unlocked() const;
243 inline bool has_bias_pattern() const;
244 inline bool has_bias_pattern_raw() const;
245
246 // asserts and guarantees
247 static bool is_oop(oop obj, bool ignore_mark_word = false);
248 static bool is_oop_or_null(oop obj, bool ignore_mark_word = false);
249 #ifndef PRODUCT
250 inline bool is_unlocked_oop() const;
251 #endif
252
253 // garbage collection
254 inline bool is_gc_marked() const;
255
256 // Forward pointer operations for scavenge
257 inline bool is_forwarded() const;
258
259 inline void forward_to(oop p);
260 inline bool cas_forward_to(oop p, markOop compare);
261
262 #if INCLUDE_ALL_GCS
263 // Like "forward_to", but inserts the forwarding pointer atomically.
264 // Exactly one thread succeeds in inserting the forwarding pointer, and
265 // this call returns "NULL" for that thread; any other thread has the
266 // value of the forwarding pointer returned and does not modify "this".
267 inline oop forward_to_atomic(oop p);
268 #endif // INCLUDE_ALL_GCS
269
270 inline oop forwardee() const;
271
272 // Age of object during scavenge
273 inline uint age() const;
274 inline void incr_age();
275
276 // mark-sweep support
277 void follow_body(int begin, int end);
278
279 // Garbage Collection support
280
281 #if INCLUDE_ALL_GCS
282 // Parallel Compact
283 inline void pc_follow_contents(ParCompactionManager* cm);
284 inline void pc_update_contents(ParCompactionManager* cm);
285 // Parallel Scavenge
286 inline void ps_push_contents(PSPromotionManager* pm);
287 #endif
288
289
290 // iterators, returns size of object
291 #define OOP_ITERATE_DECL(OopClosureType, nv_suffix) \
292 inline void oop_iterate(OopClosureType* blk); \
293 inline void oop_iterate(OopClosureType* blk, MemRegion mr); // Only in mr.
294
295 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_DECL)
296 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_DECL)
297
298 #define OOP_ITERATE_SIZE_DECL(OopClosureType, nv_suffix) \
299 inline int oop_iterate_size(OopClosureType* blk); \
300 inline int oop_iterate_size(OopClosureType* blk, MemRegion mr); // Only in mr.
301
302 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_SIZE_DECL)
303 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_SIZE_DECL)
304
305
306 #if INCLUDE_ALL_GCS
307
308 #define OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \
309 inline void oop_iterate_backwards(OopClosureType* blk);
310
311 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_BACKWARDS_DECL)
312 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_BACKWARDS_DECL)
313
314 #endif // INCLUDE_ALL_GCS
315
316 inline int oop_iterate_no_header(OopClosure* bk);
317 inline int oop_iterate_no_header(OopClosure* bk, MemRegion mr);
318
319 inline static bool is_instanceof_or_null(oop obj, Klass* klass);
320
321 // identity hash; returns the identity hash key (computes it if necessary)
322 // NOTE with the introduction of UseBiasedLocking that identity_hash() might reach a
323 // safepoint if called on a biased object. Calling code must be aware of that.
324 inline intptr_t identity_hash();
325 intptr_t slow_identity_hash();
326
327 // Alternate hashing code if string table is rehashed
328 unsigned int new_hash(juint seed);
329
330 // marks are forwarded to stack when object is locked
331 inline bool has_displaced_mark_raw() const;
332 inline markOop displaced_mark_raw() const;
333 inline void set_displaced_mark_raw(markOop m);
334
335 static bool has_klass_gap();
336
337 // for code generation
338 static int mark_offset_in_bytes() { return offset_of(oopDesc, _mark); }
339 static int klass_offset_in_bytes() { return offset_of(oopDesc, _metadata._klass); }
340 static int klass_gap_offset_in_bytes() {
341 assert(has_klass_gap(), "only applicable to compressed klass pointers");
342 return klass_offset_in_bytes() + sizeof(narrowKlass);
343 }
344
345 static bool is_archive_object(oop p) NOT_CDS_JAVA_HEAP_RETURN_(false);
346 };
347
348 #endif // SHARE_VM_OOPS_OOP_HPP