1 /*
2 * Copyright (c) 1997, 2017, 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/metadata.hpp"
32 #include "utilities/macros.hpp"
33
34 // oopDesc is the top baseclass for objects classes. The {name}Desc classes describe
35 // the format of Java objects so the fields can be accessed from C++.
36 // oopDesc is abstract.
37 // (see oopHierarchy for complete oop class hierarchy)
38 //
39 // no virtual functions allowed
40
41 extern bool always_do_update_barrier;
42
43 // Forward declarations.
44 class OopClosure;
45 class ScanClosure;
46 class FastScanClosure;
47 class FilteringClosure;
48 class BarrierSet;
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 markOop mark() const { return _mark; }
66 markOop* mark_addr() const { return (markOop*) &_mark; }
67
68 void set_mark(volatile markOop m) { _mark = m; }
69
70 inline void release_set_mark(markOop m);
71 inline markOop cas_set_mark(markOop new_mark, markOop old_mark);
72
73 // Used only to re-initialize the mark word (e.g., of promoted
74 // objects during a GC) -- requires a valid klass pointer
75 inline void init_mark();
76
77 inline Klass* klass() const;
78 inline Klass* klass_or_null() const volatile;
79 inline Klass* klass_or_null_acquire() const volatile;
80 inline Klass** klass_addr();
81 inline narrowKlass* compressed_klass_addr();
82
83 #if INCLUDE_VBC // fast oop only test (does not load klass)
84 inline bool klass_is_value_based();
85 #endif
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
116 // type test operations that don't require inclusion of oop.inline.hpp.
117 bool is_instance_noinline() const;
118 bool is_array_noinline() const;
119 bool is_objArray_noinline() const;
120 bool is_typeArray_noinline() const;
121
122 protected:
123 inline oop as_oop() const { return const_cast<oopDesc*>(this); }
124
125 private:
126 // field addresses in oop
127 inline void* field_base(int offset) const;
128
129 inline jbyte* byte_field_addr(int offset) const;
130 inline jchar* char_field_addr(int offset) const;
131 inline jboolean* bool_field_addr(int offset) const;
132 inline jint* int_field_addr(int offset) const;
133 inline jshort* short_field_addr(int offset) const;
134 inline jlong* long_field_addr(int offset) const;
135 inline jfloat* float_field_addr(int offset) const;
136 inline jdouble* double_field_addr(int offset) const;
137 inline Metadata** metadata_field_addr(int offset) const;
138
139 public:
140 // Need this as public for garbage collection.
141 template <class T> inline T* obj_field_addr(int offset) const;
142
143 // Needed for javaClasses
144 inline address* address_field_addr(int offset) const;
145
146 inline static bool is_null(oop obj) { return obj == NULL; }
147 inline static bool is_null(narrowOop obj) { return obj == 0; }
148
149 // Decode an oop pointer from a narrowOop if compressed.
150 // These are overloaded for oop and narrowOop as are the other functions
151 // below so that they can be called in template functions.
152 static inline oop decode_heap_oop_not_null(oop v) { return v; }
153 static inline oop decode_heap_oop_not_null(narrowOop v);
154 static inline oop decode_heap_oop(oop v) { return v; }
155 static inline oop decode_heap_oop(narrowOop v);
156
157 // Encode an oop pointer to a narrow oop. The or_null versions accept
158 // null oop pointer, others do not in order to eliminate the
159 // null checking branches.
160 static inline narrowOop encode_heap_oop_not_null(oop v);
161 static inline narrowOop encode_heap_oop(oop v);
162
163 // Load an oop out of the Java heap as is without decoding.
164 // Called by GC to check for null before decoding.
165 static inline narrowOop load_heap_oop(narrowOop* p);
166 static inline oop load_heap_oop(oop* p);
167
168 // Load an oop out of Java heap and decode it to an uncompressed oop.
169 static inline oop load_decode_heap_oop_not_null(narrowOop* p);
170 static inline oop load_decode_heap_oop_not_null(oop* p);
171 static inline oop load_decode_heap_oop(narrowOop* p);
172 static inline oop load_decode_heap_oop(oop* p);
173
174 // Store already encoded heap oop into the heap.
175 static inline void store_heap_oop(narrowOop* p, narrowOop v);
176 static inline void store_heap_oop(oop* p, oop v);
177
178 // Encode oop if UseCompressedOops and store into the heap.
179 static inline void encode_store_heap_oop_not_null(narrowOop* p, oop v);
180 static inline void encode_store_heap_oop_not_null(oop* p, oop v);
181 static inline void encode_store_heap_oop(narrowOop* p, oop v);
182 static inline void encode_store_heap_oop(oop* p, oop v);
183
184 // Access to fields in a instanceOop through these methods.
185 oop obj_field(int offset) const;
186 void obj_field_put(int offset, oop value);
187 void obj_field_put_raw(int offset, oop value);
188 void obj_field_put_volatile(int offset, oop value);
189
190 Metadata* metadata_field(int offset) const;
191 void metadata_field_put(int offset, Metadata* value);
192
193 Metadata* metadata_field_acquire(int offset) const;
194 void release_metadata_field_put(int offset, Metadata* value);
195
196 jbyte byte_field(int offset) const;
197 void byte_field_put(int offset, jbyte contents);
198
199 jchar char_field(int offset) const;
200 void char_field_put(int offset, jchar contents);
201
202 jboolean bool_field(int offset) const;
203 void bool_field_put(int offset, jboolean contents);
204
205 jint int_field(int offset) const;
206 void int_field_put(int offset, jint contents);
207
208 jshort short_field(int offset) const;
209 void short_field_put(int offset, jshort contents);
210
211 jlong long_field(int offset) const;
212 void long_field_put(int offset, jlong contents);
213
214 jfloat float_field(int offset) const;
215 void float_field_put(int offset, jfloat contents);
216
217 jdouble double_field(int offset) const;
218 void double_field_put(int offset, jdouble contents);
219
220 address address_field(int offset) const;
221 void address_field_put(int offset, address contents);
222
223 oop obj_field_acquire(int offset) const;
224 void release_obj_field_put(int offset, oop value);
225
226 jbyte byte_field_acquire(int offset) const;
227 void release_byte_field_put(int offset, jbyte contents);
228
229 jchar char_field_acquire(int offset) const;
230 void release_char_field_put(int offset, jchar contents);
231
232 jboolean bool_field_acquire(int offset) const;
233 void release_bool_field_put(int offset, jboolean contents);
234
235 jint int_field_acquire(int offset) const;
236 void release_int_field_put(int offset, jint contents);
237
238 jshort short_field_acquire(int offset) const;
239 void release_short_field_put(int offset, jshort contents);
240
241 jlong long_field_acquire(int offset) const;
242 void release_long_field_put(int offset, jlong contents);
243
244 jfloat float_field_acquire(int offset) const;
245 void release_float_field_put(int offset, jfloat contents);
246
247 jdouble double_field_acquire(int offset) const;
248 void release_double_field_put(int offset, jdouble contents);
249
250 address address_field_acquire(int offset) const;
251 void release_address_field_put(int offset, address contents);
252
253 // printing functions for VM debugging
254 void print_on(outputStream* st) const; // First level print
255 void print_value_on(outputStream* st) const; // Second level print.
256 void print_address_on(outputStream* st) const; // Address printing
257
258 // printing on default output stream
259 void print();
260 void print_value();
261 void print_address();
262
263 // return the print strings
264 char* print_string();
265 char* print_value_string();
266
267 // verification operations
268 void verify_on(outputStream* st);
269 void verify();
270
271 // locking operations
272 inline bool is_locked() const;
273 inline bool is_unlocked() const;
274 inline bool has_bias_pattern() const;
275
276 // asserts and guarantees
277 static bool is_oop(oop obj, bool ignore_mark_word = false);
278 static bool is_oop_or_null(oop obj, bool ignore_mark_word = false);
279 #ifndef PRODUCT
280 inline bool is_unlocked_oop() const;
281 #endif
282
283 // garbage collection
284 inline bool is_gc_marked() const;
285
286 inline bool is_scavengable() const;
287
288 // Forward pointer operations for scavenge
289 inline bool is_forwarded() const;
290
291 inline void forward_to(oop p);
292 inline bool cas_forward_to(oop p, markOop compare);
293
294 #if INCLUDE_ALL_GCS
295 // Like "forward_to", but inserts the forwarding pointer atomically.
296 // Exactly one thread succeeds in inserting the forwarding pointer, and
297 // this call returns "NULL" for that thread; any other thread has the
298 // value of the forwarding pointer returned and does not modify "this".
299 inline oop forward_to_atomic(oop p);
300 #endif // INCLUDE_ALL_GCS
301
302 inline oop forwardee() const;
303
304 // Age of object during scavenge
305 inline uint age() const;
306 inline void incr_age();
307
308 // mark-sweep support
309 void follow_body(int begin, int end);
310
311 // Garbage Collection support
312
313 #if INCLUDE_ALL_GCS
314 // Parallel Compact
315 inline void pc_follow_contents(ParCompactionManager* cm);
316 inline void pc_update_contents(ParCompactionManager* cm);
317 // Parallel Scavenge
318 inline void ps_push_contents(PSPromotionManager* pm);
319 #endif
320
321
322 // iterators, returns size of object
323 #define OOP_ITERATE_DECL(OopClosureType, nv_suffix) \
324 inline void oop_iterate(OopClosureType* blk); \
325 inline void oop_iterate(OopClosureType* blk, MemRegion mr); // Only in mr.
326
327 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_DECL)
328 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_DECL)
329
330 #define OOP_ITERATE_SIZE_DECL(OopClosureType, nv_suffix) \
331 inline int oop_iterate_size(OopClosureType* blk); \
332 inline int oop_iterate_size(OopClosureType* blk, MemRegion mr); // Only in mr.
333
334 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_SIZE_DECL)
335 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_SIZE_DECL)
336
337
338 #if INCLUDE_ALL_GCS
339
340 #define OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \
341 inline void oop_iterate_backwards(OopClosureType* blk);
342
343 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_BACKWARDS_DECL)
344 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_BACKWARDS_DECL)
345
346 #endif // INCLUDE_ALL_GCS
347
348 inline int oop_iterate_no_header(OopClosure* bk);
349 inline int oop_iterate_no_header(OopClosure* bk, MemRegion mr);
350
351 // identity hash; returns the identity hash key (computes it if necessary)
352 // NOTE with the introduction of UseBiasedLocking that identity_hash() might reach a
353 // safepoint if called on a biased object. Calling code must be aware of that.
354 inline intptr_t identity_hash();
355 intptr_t slow_identity_hash();
356
357 // Alternate hashing code if string table is rehashed
358 unsigned int new_hash(juint seed);
359
360 // marks are forwarded to stack when object is locked
361 inline bool has_displaced_mark() const;
362 inline markOop displaced_mark() const;
363 inline void set_displaced_mark(markOop m);
364
365 static bool has_klass_gap();
366
367 // for code generation
368 static int mark_offset_in_bytes() { return offset_of(oopDesc, _mark); }
369 static int klass_offset_in_bytes() { return offset_of(oopDesc, _metadata._klass); }
370 static int klass_gap_offset_in_bytes() {
371 assert(has_klass_gap(), "only applicable to compressed klass pointers");
372 return klass_offset_in_bytes() + sizeof(narrowKlass);
373 }
374
375 static bool is_archive_object(oop p) NOT_CDS_JAVA_HEAP_RETURN_(false);
376 };
377
378 #endif // SHARE_VM_OOPS_OOP_HPP