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 inline static bool is_null(oop obj) { return obj == NULL; }
135 inline static bool is_null(narrowOop obj) { return obj == 0; }
136
137 // Standard compare function returns negative value if o1 < o2
138 // 0 if o1 == o2
139 // positive value if o1 > o2
140 inline static int compare(oop o1, oop o2) {
141 void* o1_addr = (void*)o1;
142 void* o2_addr = (void*)o2;
143 if (o1_addr < o2_addr) {
144 return -1;
145 } else if (o1_addr > o2_addr) {
146 return 1;
147 } else {
148 return 0;
149 }
150 }
151
152 // Decode an oop pointer from a narrowOop if compressed.
153 // These are overloaded for oop and narrowOop as are the other functions
154 // below so that they can be called in template functions.
155 static inline oop decode_heap_oop_not_null(oop v) { return v; }
156 static inline oop decode_heap_oop_not_null(narrowOop v);
157 static inline oop decode_heap_oop(oop v) { return v; }
158 static inline oop decode_heap_oop(narrowOop v);
159
160 // Encode an oop pointer to a narrow oop. The or_null versions accept
161 // null oop pointer, others do not in order to eliminate the
162 // null checking branches.
163 static inline narrowOop encode_heap_oop_not_null(oop v);
164 static inline narrowOop encode_heap_oop(oop v);
165
166 // Load an oop out of the Java heap as is without decoding.
167 // Called by GC to check for null before decoding.
168 static inline narrowOop load_heap_oop(narrowOop* p);
169 static inline oop load_heap_oop(oop* p);
170
171 // Load an oop out of Java heap and decode it to an uncompressed oop.
172 static inline oop load_decode_heap_oop_not_null(narrowOop* p);
173 static inline oop load_decode_heap_oop_not_null(oop* p);
174 static inline oop load_decode_heap_oop(narrowOop* p);
175 static inline oop load_decode_heap_oop(oop* p);
176
177 // Store already encoded heap oop into the heap.
178 static inline void store_heap_oop(narrowOop* p, narrowOop v);
179 static inline void store_heap_oop(oop* p, oop v);
180
181 // Encode oop if UseCompressedOops and store into the heap.
182 static inline void encode_store_heap_oop_not_null(narrowOop* p, oop v);
183 static inline void encode_store_heap_oop_not_null(oop* p, oop v);
184 static inline void encode_store_heap_oop(narrowOop* p, oop v);
185 static inline void encode_store_heap_oop(oop* p, oop v);
186
187 // Access to fields in a instanceOop through these methods.
188 template <DecoratorSet decorator>
189 oop obj_field_access(int offset) const;
190 oop obj_field(int offset) const;
191 void obj_field_put(int offset, oop value);
192 void obj_field_put_raw(int offset, oop value);
193 void obj_field_put_volatile(int offset, oop value);
194
195 Metadata* metadata_field(int offset) const;
196 void metadata_field_put(int offset, Metadata* value);
197
198 Metadata* metadata_field_acquire(int offset) const;
199 void release_metadata_field_put(int offset, Metadata* value);
200
201 jbyte byte_field(int offset) const;
202 void byte_field_put(int offset, jbyte contents);
203
204 jchar char_field(int offset) const;
205 void char_field_put(int offset, jchar contents);
206
207 jboolean bool_field(int offset) const;
208 void bool_field_put(int offset, jboolean contents);
209
210 jint int_field(int offset) const;
211 void int_field_put(int offset, jint contents);
212
213 jshort short_field(int offset) const;
214 void short_field_put(int offset, jshort contents);
215
216 jlong long_field(int offset) const;
217 void long_field_put(int offset, jlong contents);
218
219 jfloat float_field(int offset) const;
220 void float_field_put(int offset, jfloat contents);
221
222 jdouble double_field(int offset) const;
223 void double_field_put(int offset, jdouble contents);
224
225 address address_field(int offset) const;
226 void address_field_put(int offset, address contents);
227
228 oop obj_field_acquire(int offset) const;
229 void release_obj_field_put(int offset, oop value);
230
231 jbyte byte_field_acquire(int offset) const;
232 void release_byte_field_put(int offset, jbyte contents);
233
234 jchar char_field_acquire(int offset) const;
235 void release_char_field_put(int offset, jchar contents);
236
237 jboolean bool_field_acquire(int offset) const;
238 void release_bool_field_put(int offset, jboolean contents);
239
240 jint int_field_acquire(int offset) const;
241 void release_int_field_put(int offset, jint contents);
242
243 jshort short_field_acquire(int offset) const;
244 void release_short_field_put(int offset, jshort contents);
245
246 jlong long_field_acquire(int offset) const;
247 void release_long_field_put(int offset, jlong contents);
248
249 jfloat float_field_acquire(int offset) const;
250 void release_float_field_put(int offset, jfloat contents);
251
252 jdouble double_field_acquire(int offset) const;
253 void release_double_field_put(int offset, jdouble contents);
254
255 address address_field_acquire(int offset) const;
256 void release_address_field_put(int offset, address contents);
257
258 // printing functions for VM debugging
259 void print_on(outputStream* st) const; // First level print
260 void print_value_on(outputStream* st) const; // Second level print.
261 void print_address_on(outputStream* st) const; // Address printing
262
263 // printing on default output stream
264 void print();
265 void print_value();
266 void print_address();
267
268 // return the print strings
269 char* print_string();
270 char* print_value_string();
271
272 // verification operations
273 void verify_on(outputStream* st);
274 void verify();
275
276 // locking operations
277 inline bool is_locked() const;
278 inline bool is_unlocked() const;
279 inline bool has_bias_pattern() const;
280 inline bool has_bias_pattern_raw() const;
281
282 // asserts and guarantees
283 static bool is_oop(oop obj, bool ignore_mark_word = false);
284 static bool is_oop_or_null(oop obj, bool ignore_mark_word = false);
285 #ifndef PRODUCT
286 inline bool is_unlocked_oop() const;
287 #endif
288
289 // garbage collection
290 inline bool is_gc_marked() const;
291
292 // Forward pointer operations for scavenge
293 inline bool is_forwarded() const;
294
295 inline void forward_to(oop p);
296 inline bool cas_forward_to(oop p, markOop compare);
297
298 #if INCLUDE_ALL_GCS
299 // Like "forward_to", but inserts the forwarding pointer atomically.
300 // Exactly one thread succeeds in inserting the forwarding pointer, and
301 // this call returns "NULL" for that thread; any other thread has the
302 // value of the forwarding pointer returned and does not modify "this".
303 inline oop forward_to_atomic(oop p);
304 #endif // INCLUDE_ALL_GCS
305
306 inline oop forwardee() const;
307
308 // Age of object during scavenge
309 inline uint age() const;
310 inline void incr_age();
311
312 // mark-sweep support
313 void follow_body(int begin, int end);
314
315 // Garbage Collection support
316
317 #if INCLUDE_ALL_GCS
318 // Parallel Compact
319 inline void pc_follow_contents(ParCompactionManager* cm);
320 inline void pc_update_contents(ParCompactionManager* cm);
321 // Parallel Scavenge
322 inline void ps_push_contents(PSPromotionManager* pm);
323 #endif
324
325
326 // iterators, returns size of object
327 #define OOP_ITERATE_DECL(OopClosureType, nv_suffix) \
328 inline void oop_iterate(OopClosureType* blk); \
329 inline void oop_iterate(OopClosureType* blk, MemRegion mr); // Only in mr.
330
331 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_DECL)
332 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_DECL)
333
334 #define OOP_ITERATE_SIZE_DECL(OopClosureType, nv_suffix) \
335 inline int oop_iterate_size(OopClosureType* blk); \
336 inline int oop_iterate_size(OopClosureType* blk, MemRegion mr); // Only in mr.
337
338 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_SIZE_DECL)
339 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_SIZE_DECL)
340
341
342 #if INCLUDE_ALL_GCS
343
344 #define OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \
345 inline void oop_iterate_backwards(OopClosureType* blk);
346
347 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_BACKWARDS_DECL)
348 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_BACKWARDS_DECL)
349
350 #endif // INCLUDE_ALL_GCS
351
352 inline int oop_iterate_no_header(OopClosure* bk);
353 inline int oop_iterate_no_header(OopClosure* bk, MemRegion mr);
354
355 // identity hash; returns the identity hash key (computes it if necessary)
356 // NOTE with the introduction of UseBiasedLocking that identity_hash() might reach a
357 // safepoint if called on a biased object. Calling code must be aware of that.
358 inline intptr_t identity_hash();
359 intptr_t slow_identity_hash();
360
361 // Alternate hashing code if string table is rehashed
362 unsigned int new_hash(juint seed);
363
364 // marks are forwarded to stack when object is locked
365 inline bool has_displaced_mark_raw() const;
366 inline markOop displaced_mark_raw() const;
367 inline void set_displaced_mark_raw(markOop m);
368
369 static bool has_klass_gap();
370
371 // for code generation
372 static int mark_offset_in_bytes() { return offset_of(oopDesc, _mark); }
373 static int klass_offset_in_bytes() { return offset_of(oopDesc, _metadata._klass); }
374 static int klass_gap_offset_in_bytes() {
375 assert(has_klass_gap(), "only applicable to compressed klass pointers");
376 return klass_offset_in_bytes() + sizeof(narrowKlass);
377 }
378
379 static bool is_archive_object(oop p) NOT_CDS_JAVA_HEAP_RETURN_(false);
380 };
381
382 #endif // SHARE_VM_OOPS_OOP_HPP