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 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 // oop only test (does not load klass)
85 inline bool klass_is_value_type();
86
87 inline void set_klass(Klass* k);
88 inline void release_set_klass(Klass* k);
89
90 // For klass field compression
91 inline int klass_gap() const;
92 inline void set_klass_gap(int z);
93 // For when the klass pointer is being used as a linked list "next" field.
94 inline void set_klass_to_list_ptr(oop k);
95 inline oop list_ptr_from_klass();
96
97 // size of object header, aligned to platform wordSize
98 static int header_size() { return sizeof(oopDesc)/HeapWordSize; }
99
100 // Returns whether this is an instance of k or an instance of a subclass of k
101 inline bool is_a(Klass* k) const;
102
103 // Returns the actual oop size of the object
104 inline int size();
105
106 // Sometimes (for complicated concurrency-related reasons), it is useful
107 // to be able to figure out the size of an object knowing its klass.
108 inline int size_given_klass(Klass* klass);
109
110 // type test operations (inlined in oop.inline.hpp)
111 inline bool is_instance() const;
112 inline bool is_array() const;
113 inline bool is_objArray() const;
114 inline bool is_typeArray() const;
115 inline bool is_value() const;
116 inline bool is_valueArray() const;
117
118 // type test operations that don't require inclusion of oop.inline.hpp.
119 bool is_instance_noinline() const;
120 bool is_array_noinline() const;
121 bool is_objArray_noinline() const;
122 bool is_typeArray_noinline() const;
123 bool is_value_noinline() const;
124 bool is_valueArray_noinline() const;
125
126 protected:
127 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 inline static bool is_null(oop obj) { return obj == NULL; }
138 inline static bool is_null(narrowOop obj) { return obj == 0; }
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 // Decode an oop pointer from a narrowOop if compressed.
156 // These are overloaded for oop and narrowOop as are the other functions
157 // below so that they can be called in template functions.
158 static inline oop decode_heap_oop_not_null(oop v) { return v; }
159 static inline oop decode_heap_oop_not_null(narrowOop v);
160 static inline oop decode_heap_oop(oop v) { return v; }
161 static inline oop decode_heap_oop(narrowOop v);
162
163 // Encode an oop pointer to a narrow oop. The or_null versions accept
164 // null oop pointer, others do not in order to eliminate the
165 // null checking branches.
166 static inline narrowOop encode_heap_oop_not_null(oop v);
167 static inline narrowOop encode_heap_oop(oop v);
168
169 // Load an oop out of the Java heap as is without decoding.
170 // Called by GC to check for null before decoding.
171 static inline narrowOop load_heap_oop(narrowOop* p);
172 static inline oop load_heap_oop(oop* p);
173
174 // Load an oop out of Java heap and decode it to an uncompressed oop.
175 static inline oop load_decode_heap_oop_not_null(narrowOop* p);
176 static inline oop load_decode_heap_oop_not_null(oop* p);
177 static inline oop load_decode_heap_oop(narrowOop* p);
178 static inline oop load_decode_heap_oop(oop* p);
179
180 // Store already encoded heap oop into the heap.
181 static inline void store_heap_oop(narrowOop* p, narrowOop v);
182 static inline void store_heap_oop(oop* p, oop v);
183
184 // Encode oop if UseCompressedOops and store into the heap.
185 static inline void encode_store_heap_oop_not_null(narrowOop* p, oop v);
186 static inline void encode_store_heap_oop_not_null(oop* p, oop v);
187 static inline void encode_store_heap_oop(narrowOop* p, oop v);
188 static inline void encode_store_heap_oop(oop* p, oop v);
189
190 // Access to fields in a instanceOop through these methods.
191 template <DecoratorSet decorator>
192 oop obj_field_access(int offset) const;
193 oop obj_field(int offset) const;
194 void obj_field_put(int offset, oop value);
195 void obj_field_put_raw(int offset, oop value);
196 void obj_field_put_volatile(int offset, oop value);
197
198 Metadata* metadata_field(int offset) const;
199 void metadata_field_put(int offset, Metadata* value);
200
201 Metadata* metadata_field_acquire(int offset) const;
202 void release_metadata_field_put(int offset, Metadata* value);
203
204 jbyte byte_field(int offset) const;
205 void byte_field_put(int offset, jbyte contents);
206
207 jchar char_field(int offset) const;
208 void char_field_put(int offset, jchar contents);
209
210 jboolean bool_field(int offset) const;
211 void bool_field_put(int offset, jboolean contents);
212
213 jint int_field(int offset) const;
214 void int_field_put(int offset, jint contents);
215
216 jshort short_field(int offset) const;
217 void short_field_put(int offset, jshort contents);
218
219 jlong long_field(int offset) const;
220 void long_field_put(int offset, jlong contents);
221
222 jfloat float_field(int offset) const;
223 void float_field_put(int offset, jfloat contents);
224
225 jdouble double_field(int offset) const;
226 void double_field_put(int offset, jdouble contents);
227
228 address address_field(int offset) const;
229 void address_field_put(int offset, address contents);
230
231 oop obj_field_acquire(int offset) const;
232 void release_obj_field_put(int offset, oop value);
233
234 jbyte byte_field_acquire(int offset) const;
235 void release_byte_field_put(int offset, jbyte contents);
236
237 jchar char_field_acquire(int offset) const;
238 void release_char_field_put(int offset, jchar contents);
239
240 jboolean bool_field_acquire(int offset) const;
241 void release_bool_field_put(int offset, jboolean contents);
242
243 jint int_field_acquire(int offset) const;
244 void release_int_field_put(int offset, jint contents);
245
246 jshort short_field_acquire(int offset) const;
247 void release_short_field_put(int offset, jshort contents);
248
249 jlong long_field_acquire(int offset) const;
250 void release_long_field_put(int offset, jlong contents);
251
252 jfloat float_field_acquire(int offset) const;
253 void release_float_field_put(int offset, jfloat contents);
254
255 jdouble double_field_acquire(int offset) const;
256 void release_double_field_put(int offset, jdouble contents);
257
258 address address_field_acquire(int offset) const;
259 void release_address_field_put(int offset, address contents);
260
261 // printing functions for VM debugging
262 void print_on(outputStream* st) const; // First level print
263 void print_value_on(outputStream* st) const; // Second level print.
264 void print_address_on(outputStream* st) const; // Address printing
265
266 // printing on default output stream
267 void print();
268 void print_value();
269 void print_address();
270
271 // return the print strings
272 char* print_string();
273 char* print_value_string();
274
275 // verification operations
276 void verify_on(outputStream* st);
277 void verify();
278
279 // locking operations
280 inline bool is_locked() const;
281 inline bool is_unlocked() const;
282 inline bool has_bias_pattern() const;
283
284 // asserts and guarantees
285 static bool is_oop(oop obj, bool ignore_mark_word = false);
286 static bool is_oop_or_null(oop obj, bool ignore_mark_word = false);
287 #ifndef PRODUCT
288 inline bool is_unlocked_oop() const;
289 #endif
290
291 // garbage collection
292 inline bool is_gc_marked() const;
293
294 inline bool is_scavengable() const;
295
296 // Forward pointer operations for scavenge
297 inline bool is_forwarded() const;
298
299 inline void forward_to(oop p);
300 inline bool cas_forward_to(oop p, markOop compare);
301
302 #if INCLUDE_ALL_GCS
303 // Like "forward_to", but inserts the forwarding pointer atomically.
304 // Exactly one thread succeeds in inserting the forwarding pointer, and
305 // this call returns "NULL" for that thread; any other thread has the
306 // value of the forwarding pointer returned and does not modify "this".
307 inline oop forward_to_atomic(oop p);
308 #endif // INCLUDE_ALL_GCS
309
310 inline oop forwardee() const;
311
312 // Age of object during scavenge
313 inline uint age() const;
314 inline void incr_age();
315
316 // mark-sweep support
317 void follow_body(int begin, int end);
318
319 // Garbage Collection support
320
321 #if INCLUDE_ALL_GCS
322 // Parallel Compact
323 inline void pc_follow_contents(ParCompactionManager* cm);
324 inline void pc_update_contents(ParCompactionManager* cm);
325 // Parallel Scavenge
326 inline void ps_push_contents(PSPromotionManager* pm);
327 #endif
328
329
330 // iterators, returns size of object
331 #define OOP_ITERATE_DECL(OopClosureType, nv_suffix) \
332 inline void oop_iterate(OopClosureType* blk); \
333 inline void oop_iterate(OopClosureType* blk, MemRegion mr); // Only in mr.
334
335 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_DECL)
336 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_DECL)
337
338 #define OOP_ITERATE_SIZE_DECL(OopClosureType, nv_suffix) \
339 inline int oop_iterate_size(OopClosureType* blk); \
340 inline int oop_iterate_size(OopClosureType* blk, MemRegion mr); // Only in mr.
341
342 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_SIZE_DECL)
343 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_SIZE_DECL)
344
345
346 #if INCLUDE_ALL_GCS
347
348 #define OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \
349 inline void oop_iterate_backwards(OopClosureType* blk);
350
351 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_BACKWARDS_DECL)
352 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_BACKWARDS_DECL)
353
354 #endif // INCLUDE_ALL_GCS
355
356 inline int oop_iterate_no_header(OopClosure* bk);
357 inline int oop_iterate_no_header(OopClosure* bk, MemRegion mr);
358
359 // identity hash; returns the identity hash key (computes it if necessary)
360 // NOTE with the introduction of UseBiasedLocking that identity_hash() might reach a
361 // safepoint if called on a biased object. Calling code must be aware of that.
362 inline intptr_t identity_hash();
363 intptr_t slow_identity_hash();
364
365 // Alternate hashing code if string table is rehashed
366 unsigned int new_hash(juint seed);
367
368 // marks are forwarded to stack when object is locked
369 inline bool has_displaced_mark() const;
370 inline markOop displaced_mark() const;
371 inline void set_displaced_mark(markOop m);
372
373 static bool has_klass_gap();
374
375 // for code generation
376 static int mark_offset_in_bytes() { return offset_of(oopDesc, _mark); }
377 static int klass_offset_in_bytes() { return offset_of(oopDesc, _metadata._klass); }
378 static int klass_gap_offset_in_bytes() {
379 assert(has_klass_gap(), "only applicable to compressed klass pointers");
380 return klass_offset_in_bytes() + sizeof(narrowKlass);
381 }
382
383 static bool is_archive_object(oop p) NOT_CDS_JAVA_HEAP_RETURN_(false);
384 };
385
386 #endif // SHARE_VM_OOPS_OOP_HPP