1 /*
2 * Copyright (c) 1997, 2014, 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.
18 *
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 "memory/iterator.hpp"
29 #include "memory/memRegion.hpp"
30 #include "memory/specialized_oop_closures.hpp"
31 #include "oops/metadata.hpp"
32 #include "utilities/macros.hpp"
33 #include "utilities/top.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 // store into oop with store check
43 template <class T> void oop_store(T* p, oop v);
44 template <class T> void oop_store(volatile T* p, oop v);
45
46 extern bool always_do_update_barrier;
47
48 // Forward declarations.
49 class OopClosure;
50 class ScanClosure;
51 class FastScanClosure;
52 class FilteringClosure;
53 class BarrierSet;
54 class CMSIsAliveClosure;
55
56 class PSPromotionManager;
57 class ParCompactionManager;
58
59 class oopDesc {
60 friend class VMStructs;
61 private:
62 volatile markOop _mark;
63 union _metadata {
64 Klass* _klass;
65 narrowKlass _compressed_klass;
66 } _metadata;
67
68 // Fast access to barrier set. Must be initialized.
69 static BarrierSet* _bs;
70
71 public:
72 markOop mark() const { return _mark; }
73 markOop* mark_addr() const { return (markOop*) &_mark; }
74
75 void set_mark(volatile markOop m) { _mark = m; }
76
77 void release_set_mark(markOop m);
78 markOop cas_set_mark(markOop new_mark, markOop old_mark);
79
80 // Used only to re-initialize the mark word (e.g., of promoted
81 // objects during a GC) -- requires a valid klass pointer
82 void init_mark();
83
84 Klass* klass() const;
85 Klass* klass_or_null() const volatile;
86 Klass* klass_or_null_acquire() const volatile;
87 Klass** klass_addr();
88 narrowKlass* compressed_klass_addr();
89
90 void set_klass(Klass* k);
91 void release_set_klass(Klass* k);
92
93 // For klass field compression
94 int klass_gap() const;
95 void set_klass_gap(int z);
96 // For when the klass pointer is being used as a linked list "next" field.
97 void set_klass_to_list_ptr(oop k);
98 oop list_ptr_from_klass();
99
100 // size of object header, aligned to platform wordSize
101 static int header_size() { return sizeof(oopDesc)/HeapWordSize; }
102
103 // Returns whether this is an instance of k or an instance of a subclass of k
104 bool is_a(Klass* k) const;
105
106 // Returns the actual oop size of the object
107 int size();
108
109 // Sometimes (for complicated concurrency-related reasons), it is useful
110 // to be able to figure out the size of an object knowing its klass.
111 int size_given_klass(Klass* klass);
112
113 // type test operations (inlined in oop.inline.h)
114 bool is_instance() const;
115 bool is_instanceMirror() const;
116 bool is_instanceClassLoader() const;
117 bool is_instanceRef() const;
118 bool is_array() const;
119 bool is_objArray() const;
120 bool is_typeArray() const;
121
122 private:
123 // field addresses in oop
124 void* field_base(int offset) const;
125
126 jbyte* byte_field_addr(int offset) const;
127 jchar* char_field_addr(int offset) const;
128 jboolean* bool_field_addr(int offset) const;
129 jint* int_field_addr(int offset) const;
130 jshort* short_field_addr(int offset) const;
131 jlong* long_field_addr(int offset) const;
132 jfloat* float_field_addr(int offset) const;
133 jdouble* double_field_addr(int offset) const;
134 Metadata** metadata_field_addr(int offset) const;
135
136 public:
137 // Need this as public for garbage collection.
138 template <class T> T* obj_field_addr(int offset) const;
139
140 // Needed for javaClasses
141 address* address_field_addr(int offset) const;
142
143 static bool is_null(oop obj);
144 static bool is_null(narrowOop obj);
145 static bool is_null(Klass* obj);
146
147 // Decode an oop pointer from a narrowOop if compressed.
148 // These are overloaded for oop and narrowOop as are the other functions
149 // below so that they can be called in template functions.
150 static oop decode_heap_oop_not_null(oop v);
151 static oop decode_heap_oop_not_null(narrowOop v);
152 static oop decode_heap_oop(oop v);
153 static oop decode_heap_oop(narrowOop v);
154
155 // Encode an oop pointer to a narrow oop. The or_null versions accept
156 // null oop pointer, others do not in order to eliminate the
157 // null checking branches.
158 static narrowOop encode_heap_oop_not_null(oop v);
159 static narrowOop encode_heap_oop(oop v);
160
161 // Load an oop out of the Java heap
162 static narrowOop load_heap_oop(narrowOop* p);
163 static oop load_heap_oop(oop* p);
164
165 // Load an oop out of Java heap and decode it to an uncompressed oop.
166 static oop load_decode_heap_oop_not_null(narrowOop* p);
167 static oop load_decode_heap_oop_not_null(oop* p);
168 static oop load_decode_heap_oop(narrowOop* p);
169 static oop load_decode_heap_oop(oop* p);
170
171 // Store an oop into the heap.
172 static void store_heap_oop(narrowOop* p, narrowOop v);
173 static void store_heap_oop(oop* p, oop v);
174
175 // Encode oop if UseCompressedOops and store into the heap.
176 static void encode_store_heap_oop_not_null(narrowOop* p, oop v);
177 static void encode_store_heap_oop_not_null(oop* p, oop v);
178 static void encode_store_heap_oop(narrowOop* p, oop v);
179 static void encode_store_heap_oop(oop* p, oop v);
180
181 static void release_store_heap_oop(volatile narrowOop* p, narrowOop v);
182 static void release_store_heap_oop(volatile oop* p, oop v);
183
184 static void release_encode_store_heap_oop_not_null(volatile narrowOop* p, oop v);
185 static void release_encode_store_heap_oop_not_null(volatile oop* p, oop v);
186 static void release_encode_store_heap_oop(volatile narrowOop* p, oop v);
187 static void release_encode_store_heap_oop(volatile oop* p, oop v);
188
189 static oop atomic_exchange_oop(oop exchange_value, volatile HeapWord *dest);
190 static oop atomic_compare_exchange_oop(oop exchange_value,
191 volatile HeapWord *dest,
192 oop compare_value,
193 bool prebarrier = false);
194
195 // Access to fields in a instanceOop through these methods.
196 oop obj_field(int offset) const;
197 volatile oop obj_field_volatile(int offset) const;
198 void obj_field_put(int offset, oop value);
199 void obj_field_put_raw(int offset, oop value);
200 void obj_field_put_volatile(int offset, oop value);
201
202 Metadata* metadata_field(int offset) const;
203 void metadata_field_put(int offset, Metadata* value);
204
205 jbyte byte_field(int offset) const;
206 void byte_field_put(int offset, jbyte contents);
207
208 jchar char_field(int offset) const;
209 void char_field_put(int offset, jchar contents);
210
211 jboolean bool_field(int offset) const;
212 void bool_field_put(int offset, jboolean contents);
213
214 jint int_field(int offset) const;
215 void int_field_put(int offset, jint contents);
216
217 jshort short_field(int offset) const;
218 void short_field_put(int offset, jshort contents);
219
220 jlong long_field(int offset) const;
221 void long_field_put(int offset, jlong contents);
222
223 jfloat float_field(int offset) const;
224 void float_field_put(int offset, jfloat contents);
225
226 jdouble double_field(int offset) const;
227 void double_field_put(int offset, jdouble contents);
228
229 address address_field(int offset) const;
230 void address_field_put(int offset, address contents);
231
232 oop obj_field_acquire(int offset) const;
233 void release_obj_field_put(int offset, oop value);
234
235 jbyte byte_field_acquire(int offset) const;
236 void release_byte_field_put(int offset, jbyte contents);
237
238 jchar char_field_acquire(int offset) const;
239 void release_char_field_put(int offset, jchar contents);
240
241 jboolean bool_field_acquire(int offset) const;
242 void release_bool_field_put(int offset, jboolean contents);
243
244 jint int_field_acquire(int offset) const;
245 void release_int_field_put(int offset, jint contents);
246
247 jshort short_field_acquire(int offset) const;
248 void release_short_field_put(int offset, jshort contents);
249
250 jlong long_field_acquire(int offset) const;
251 void release_long_field_put(int offset, jlong contents);
252
253 jfloat float_field_acquire(int offset) const;
254 void release_float_field_put(int offset, jfloat contents);
255
256 jdouble double_field_acquire(int offset) const;
257 void release_double_field_put(int offset, jdouble contents);
258
259 address address_field_acquire(int offset) const;
260 void release_address_field_put(int offset, address contents);
261
262 // printing functions for VM debugging
263 void print_on(outputStream* st) const; // First level print
264 void print_value_on(outputStream* st) const; // Second level print.
265 void print_address_on(outputStream* st) const; // Address printing
266
267 // printing on default output stream
268 void print();
269 void print_value();
270 void print_address();
271
272 // return the print strings
273 char* print_string();
274 char* print_value_string();
275
276 // verification operations
277 void verify_on(outputStream* st);
278 void verify();
279
280 // locking operations
281 bool is_locked() const;
282 bool is_unlocked() const;
283 bool has_bias_pattern() const;
284
285 // asserts
286 bool is_oop(bool ignore_mark_word = false) const;
287 bool is_oop_or_null(bool ignore_mark_word = false) const;
288 #ifndef PRODUCT
289 bool is_unlocked_oop() const;
290 #endif
291
292 // garbage collection
293 bool is_gc_marked() const;
294 // Apply "MarkSweep::mark_and_push" to (the address of) every non-NULL
295 // reference field in "this".
296 void follow_contents(void);
297
298 #if INCLUDE_ALL_GCS
299 // Parallel Scavenge
300 void push_contents(PSPromotionManager* pm);
301
302 // Parallel Old
303 void update_contents(ParCompactionManager* cm);
304
305 void follow_contents(ParCompactionManager* cm);
306 #endif // INCLUDE_ALL_GCS
307
308 bool is_scavengable() const;
309
310 // Forward pointer operations for scavenge
311 bool is_forwarded() const;
312
313 void forward_to(oop p);
314 bool cas_forward_to(oop p, markOop compare);
315
316 #if INCLUDE_ALL_GCS
317 // Like "forward_to", but inserts the forwarding pointer atomically.
318 // Exactly one thread succeeds in inserting the forwarding pointer, and
319 // this call returns "NULL" for that thread; any other thread has the
320 // value of the forwarding pointer returned and does not modify "this".
321 oop forward_to_atomic(oop p);
322 #endif // INCLUDE_ALL_GCS
323
324 oop forwardee() const;
325
326 // Age of object during scavenge
327 uint age() const;
328 void incr_age();
329
330 // Adjust all pointers in this object to point at it's forwarded location and
331 // return the size of this oop. This is used by the MarkSweep collector.
332 int adjust_pointers();
333
334 // mark-sweep support
335 void follow_body(int begin, int end);
336
337 // Fast access to barrier set
338 static BarrierSet* bs() { return _bs; }
339 static void set_bs(BarrierSet* bs) { _bs = bs; }
340
341 // iterators, returns size of object
342 #define OOP_ITERATE_DECL(OopClosureType, nv_suffix) \
343 int oop_iterate(OopClosureType* blk); \
344 int oop_iterate(OopClosureType* blk, MemRegion mr); // Only in mr.
345
346 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_DECL)
347 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_DECL)
348
349 #if INCLUDE_ALL_GCS
350
351 #define OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \
352 int oop_iterate_backwards(OopClosureType* blk);
353
354 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_BACKWARDS_DECL)
355 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_BACKWARDS_DECL)
356 #endif
357
358 int oop_iterate_no_header(OopClosure* bk);
359 int oop_iterate_no_header(OopClosure* bk, MemRegion mr);
360
361 // identity hash; returns the identity hash key (computes it if necessary)
362 // NOTE with the introduction of UseBiasedLocking that identity_hash() might reach a
363 // safepoint if called on a biased object. Calling code must be aware of that.
364 intptr_t identity_hash();
365 intptr_t slow_identity_hash();
366
367 // Alternate hashing code if string table is rehashed
368 unsigned int new_hash(juint seed);
369
370 // marks are forwarded to stack when object is locked
371 bool has_displaced_mark() const;
372 markOop displaced_mark() const;
373 void set_displaced_mark(markOop m);
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 };
380
381 #endif // SHARE_VM_OOPS_OOP_HPP