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/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 private:
123 // field addresses in oop
124 inline void* field_base(int offset) const;
125
126 inline jbyte* byte_field_addr(int offset) const;
127 inline jchar* char_field_addr(int offset) const;
128 inline jboolean* bool_field_addr(int offset) const;
129 inline jint* int_field_addr(int offset) const;
130 inline jshort* short_field_addr(int offset) const;
131 inline jlong* long_field_addr(int offset) const;
132 inline jfloat* float_field_addr(int offset) const;
133 inline jdouble* double_field_addr(int offset) const;
134 inline Metadata** metadata_field_addr(int offset) const;
135
136 public:
137 // Need this as public for garbage collection.
138 template <class T> inline T* obj_field_addr(int offset) const;
139
140 // Needed for javaClasses
141 inline address* address_field_addr(int offset) const;
142
143 inline static bool is_null(oop obj) { return obj == NULL; }
144 inline static bool is_null(narrowOop obj) { return obj == 0; }
145
146 // Decode an oop pointer from a narrowOop if compressed.
147 // These are overloaded for oop and narrowOop as are the other functions
148 // below so that they can be called in template functions.
149 static inline oop decode_heap_oop_not_null(oop v) { return v; }
150 static inline oop decode_heap_oop_not_null(narrowOop v);
151 static inline oop decode_heap_oop(oop v) { return v; }
152 static inline oop decode_heap_oop(narrowOop v);
153
154 // Encode an oop pointer to a narrow oop. The or_null versions accept
155 // null oop pointer, others do not in order to eliminate the
156 // null checking branches.
157 static inline narrowOop encode_heap_oop_not_null(oop v);
158 static inline narrowOop encode_heap_oop(oop v);
159
160 // Load an oop out of the Java heap as is without decoding.
161 // Called by GC to check for null before decoding.
162 static inline narrowOop load_heap_oop(narrowOop* p);
163 static inline oop load_heap_oop(oop* p);
164
165 // Load an oop out of Java heap and decode it to an uncompressed oop.
166 static inline oop load_decode_heap_oop_not_null(narrowOop* p);
167 static inline oop load_decode_heap_oop_not_null(oop* p);
168 static inline oop load_decode_heap_oop(narrowOop* p);
169 static inline oop load_decode_heap_oop(oop* p);
170
171 // Store already encoded heap oop into the heap.
172 static inline void store_heap_oop(narrowOop* p, narrowOop v);
173 static inline void store_heap_oop(oop* p, oop v);
174
175 // Encode oop if UseCompressedOops and store into the heap.
176 static inline void encode_store_heap_oop_not_null(narrowOop* p, oop v);
177 static inline void encode_store_heap_oop_not_null(oop* p, oop v);
178 static inline void encode_store_heap_oop(narrowOop* p, oop v);
179 static inline void encode_store_heap_oop(oop* p, oop v);
180
181 // Access to fields in a instanceOop through these methods.
182 template <DecoratorSet decorator>
183 oop obj_field_special(int offset) const;
184 oop obj_field(int offset) const;
185 void obj_field_put(int offset, oop value);
186 void obj_field_put_raw(int offset, oop value);
187 void obj_field_put_volatile(int offset, oop value);
188
189 Metadata* metadata_field(int offset) const;
190 void metadata_field_put(int offset, Metadata* value);
191
192 Metadata* metadata_field_acquire(int offset) const;
193 void release_metadata_field_put(int offset, Metadata* value);
194
195 jbyte byte_field(int offset) const;
196 void byte_field_put(int offset, jbyte contents);
197
198 jchar char_field(int offset) const;
199 void char_field_put(int offset, jchar contents);
200
201 jboolean bool_field(int offset) const;
202 void bool_field_put(int offset, jboolean contents);
203
204 jint int_field(int offset) const;
205 void int_field_put(int offset, jint contents);
206
207 jshort short_field(int offset) const;
208 void short_field_put(int offset, jshort contents);
209
210 jlong long_field(int offset) const;
211 void long_field_put(int offset, jlong contents);
212
213 jfloat float_field(int offset) const;
214 void float_field_put(int offset, jfloat contents);
215
216 jdouble double_field(int offset) const;
217 void double_field_put(int offset, jdouble contents);
218
219 address address_field(int offset) const;
220 void address_field_put(int offset, address contents);
221
222 oop obj_field_acquire(int offset) const;
223 void release_obj_field_put(int offset, oop value);
224
225 jbyte byte_field_acquire(int offset) const;
226 void release_byte_field_put(int offset, jbyte contents);
227
228 jchar char_field_acquire(int offset) const;
229 void release_char_field_put(int offset, jchar contents);
230
231 jboolean bool_field_acquire(int offset) const;
232 void release_bool_field_put(int offset, jboolean contents);
233
234 jint int_field_acquire(int offset) const;
235 void release_int_field_put(int offset, jint contents);
236
237 jshort short_field_acquire(int offset) const;
238 void release_short_field_put(int offset, jshort contents);
239
240 jlong long_field_acquire(int offset) const;
241 void release_long_field_put(int offset, jlong contents);
242
243 jfloat float_field_acquire(int offset) const;
244 void release_float_field_put(int offset, jfloat contents);
245
246 jdouble double_field_acquire(int offset) const;
247 void release_double_field_put(int offset, jdouble contents);
248
249 address address_field_acquire(int offset) const;
250 void release_address_field_put(int offset, address contents);
251
252 // printing functions for VM debugging
253 void print_on(outputStream* st) const; // First level print
254 void print_value_on(outputStream* st) const; // Second level print.
255 void print_address_on(outputStream* st) const; // Address printing
256
257 // printing on default output stream
258 void print();
259 void print_value();
260 void print_address();
261
262 // return the print strings
263 char* print_string();
264 char* print_value_string();
265
266 // verification operations
267 void verify_on(outputStream* st);
268 void verify();
269
270 // locking operations
271 inline bool is_locked() const;
272 inline bool is_unlocked() const;
273 inline bool has_bias_pattern() const;
274
275 // asserts and guarantees
276 static bool is_oop(oop obj, bool ignore_mark_word = false);
277 static bool is_oop_or_null(oop obj, bool ignore_mark_word = false);
278 #ifndef PRODUCT
279 inline bool is_unlocked_oop() const;
280 #endif
281
282 // garbage collection
283 inline bool is_gc_marked() const;
284
285 inline bool is_scavengable() const;
286
287 // Forward pointer operations for scavenge
288 inline bool is_forwarded() const;
289
290 inline void forward_to(oop p);
291 inline bool cas_forward_to(oop p, markOop compare);
292
293 #if INCLUDE_ALL_GCS
294 // Like "forward_to", but inserts the forwarding pointer atomically.
295 // Exactly one thread succeeds in inserting the forwarding pointer, and
296 // this call returns "NULL" for that thread; any other thread has the
297 // value of the forwarding pointer returned and does not modify "this".
298 inline oop forward_to_atomic(oop p);
299 #endif // INCLUDE_ALL_GCS
300
301 inline oop forwardee() const;
302
303 // Age of object during scavenge
304 inline uint age() const;
305 inline void incr_age();
306
307 // mark-sweep support
308 void follow_body(int begin, int end);
309
310 // Garbage Collection support
311
312 #if INCLUDE_ALL_GCS
313 // Parallel Compact
314 inline void pc_follow_contents(ParCompactionManager* cm);
315 inline void pc_update_contents(ParCompactionManager* cm);
316 // Parallel Scavenge
317 inline void ps_push_contents(PSPromotionManager* pm);
318 #endif
319
320
321 // iterators, returns size of object
322 #define OOP_ITERATE_DECL(OopClosureType, nv_suffix) \
323 inline void oop_iterate(OopClosureType* blk); \
324 inline void oop_iterate(OopClosureType* blk, MemRegion mr); // Only in mr.
325
326 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_DECL)
327 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_DECL)
328
329 #define OOP_ITERATE_SIZE_DECL(OopClosureType, nv_suffix) \
330 inline int oop_iterate_size(OopClosureType* blk); \
331 inline int oop_iterate_size(OopClosureType* blk, MemRegion mr); // Only in mr.
332
333 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_SIZE_DECL)
334 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_SIZE_DECL)
335
336
337 #if INCLUDE_ALL_GCS
338
339 #define OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \
340 inline void oop_iterate_backwards(OopClosureType* blk);
341
342 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_BACKWARDS_DECL)
343 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_BACKWARDS_DECL)
344
345 #endif // INCLUDE_ALL_GCS
346
347 inline int oop_iterate_no_header(OopClosure* bk);
348 inline int oop_iterate_no_header(OopClosure* bk, MemRegion mr);
349
350 // identity hash; returns the identity hash key (computes it if necessary)
351 // NOTE with the introduction of UseBiasedLocking that identity_hash() might reach a
352 // safepoint if called on a biased object. Calling code must be aware of that.
353 inline intptr_t identity_hash();
354 intptr_t slow_identity_hash();
355
356 // Alternate hashing code if string table is rehashed
357 unsigned int new_hash(juint seed);
358
359 // marks are forwarded to stack when object is locked
360 inline bool has_displaced_mark() const;
361 inline markOop displaced_mark() const;
362 inline void set_displaced_mark(markOop m);
363
364 static bool has_klass_gap();
365
366 // for code generation
367 static int mark_offset_in_bytes() { return offset_of(oopDesc, _mark); }
368 static int klass_offset_in_bytes() { return offset_of(oopDesc, _metadata._klass); }
369 static int klass_gap_offset_in_bytes() {
370 assert(has_klass_gap(), "only applicable to compressed klass pointers");
371 return klass_offset_in_bytes() + sizeof(narrowKlass);
372 }
373
374 static bool is_archive_object(oop p) NOT_CDS_JAVA_HEAP_RETURN_(false);
375 };
376
377 #endif // SHARE_VM_OOPS_OOP_HPP