1 /*
2 * Copyright (c) 1997, 2010, 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
21 * questions.
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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 "utilities/top.hpp"
32
33 // oopDesc is the top baseclass for objects classes. The {name}Desc classes describe
34 // the format of Java objects so the fields can be accessed from C++.
35 // oopDesc is abstract.
36 // (see oopHierarchy for complete oop class hierarchy)
37 //
38 // no virtual functions allowed
39
40 // store into oop with store check
41 template <class T> void oop_store(T* p, oop v);
42 template <class T> void oop_store(volatile T* p, oop v);
43
44 // store into oop without store check
45 template <class T> void oop_store_without_check(T* p, oop v);
46 template <class T> void oop_store_without_check(volatile T* p, oop v);
47
48 extern bool always_do_update_barrier;
49
50 // Forward declarations.
51 class OopClosure;
52 class ScanClosure;
53 class FastScanClosure;
54 class FilteringClosure;
55 class BarrierSet;
56 class CMSIsAliveClosure;
57
58 class PSPromotionManager;
59 class ParCompactionManager;
60
61 class oopDesc {
62 friend class VMStructs;
63 private:
64 volatile markOop _mark;
65 union _metadata {
66 wideKlassOop _klass;
67 narrowOop _compressed_klass;
68 } _metadata;
69
70 // Fast access to barrier set. Must be initialized.
71 static BarrierSet* _bs;
72
73 public:
74 markOop mark() const { return _mark; }
75 markOop* mark_addr() const { return (markOop*) &_mark; }
76
77 void set_mark(volatile markOop m) { _mark = m; }
78
79 void release_set_mark(markOop m);
80 markOop cas_set_mark(markOop new_mark, markOop old_mark);
81
82 // Used only to re-initialize the mark word (e.g., of promoted
83 // objects during a GC) -- requires a valid klass pointer
84 void init_mark();
85
86 klassOop klass() const;
87 klassOop klass_or_null() const volatile;
88 oop* klass_addr();
89 narrowOop* compressed_klass_addr();
90
91 void set_klass(klassOop 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
99 // size of object header, aligned to platform wordSize
100 static int header_size() { return sizeof(oopDesc)/HeapWordSize; }
101
102 Klass* blueprint() const;
103
104 // Returns whether this is an instance of k or an instance of a subclass of k
105 bool is_a(klassOop k) const;
106
107 // Returns the actual oop size of the object
108 int size();
109
110 // Sometimes (for complicated concurrency-related reasons), it is useful
111 // to be able to figure out the size of an object knowing its klass.
112 int size_given_klass(Klass* klass);
113
114 // Some perm gen objects are not parseble immediately after
115 // installation of their klass pointer.
116 bool is_parsable();
117
118 // Some perm gen objects that have been allocated and initialized
119 // can be changed by the VM when not at a safe point (class rededfinition
120 // is an example). Such objects should not be examined by the
121 // concurrent processing of a garbage collector if is_conc_safe()
122 // returns false.
123 bool is_conc_safe();
124
125 // type test operations (inlined in oop.inline.h)
126 bool is_instance() const;
127 bool is_instanceRef() const;
128 bool is_array() const;
129 bool is_objArray() const;
130 bool is_symbol() const;
131 bool is_klass() const;
132 bool is_thread() const;
133 bool is_method() const;
134 bool is_constMethod() const;
135 bool is_methodData() const;
136 bool is_constantPool() const;
137 bool is_constantPoolCache() const;
138 bool is_typeArray() const;
139 bool is_javaArray() const;
140 bool is_compiledICHolder() const;
141
142 private:
143 // field addresses in oop
144 void* field_base(int offset) const;
145
146 jbyte* byte_field_addr(int offset) const;
147 jchar* char_field_addr(int offset) const;
148 jboolean* bool_field_addr(int offset) const;
149 jint* int_field_addr(int offset) const;
150 jshort* short_field_addr(int offset) const;
151 jlong* long_field_addr(int offset) const;
152 jfloat* float_field_addr(int offset) const;
153 jdouble* double_field_addr(int offset) const;
154 address* address_field_addr(int offset) const;
155
156 public:
157 // Need this as public for garbage collection.
158 template <class T> T* obj_field_addr(int offset) const;
159
160 static bool is_null(oop obj);
161 static bool is_null(narrowOop obj);
162
163 // Decode an oop pointer from a narrowOop if compressed.
164 // These are overloaded for oop and narrowOop as are the other functions
165 // below so that they can be called in template functions.
166 static oop decode_heap_oop_not_null(oop v);
167 static oop decode_heap_oop_not_null(narrowOop v);
168 static oop decode_heap_oop(oop v);
169 static oop decode_heap_oop(narrowOop v);
170
171 // Encode an oop pointer to a narrow oop. The or_null versions accept
172 // null oop pointer, others do not in order to eliminate the
173 // null checking branches.
174 static narrowOop encode_heap_oop_not_null(oop v);
175 static narrowOop encode_heap_oop(oop v);
176
177 // Load an oop out of the Java heap
178 static narrowOop load_heap_oop(narrowOop* p);
179 static oop load_heap_oop(oop* p);
180
181 // Load an oop out of Java heap and decode it to an uncompressed oop.
182 static oop load_decode_heap_oop_not_null(narrowOop* p);
183 static oop load_decode_heap_oop_not_null(oop* p);
184 static oop load_decode_heap_oop(narrowOop* p);
185 static oop load_decode_heap_oop(oop* p);
186
187 // Store an oop into the heap.
188 static void store_heap_oop(narrowOop* p, narrowOop v);
189 static void store_heap_oop(oop* p, oop v);
190
191 // Encode oop if UseCompressedOops and store into the heap.
192 static void encode_store_heap_oop_not_null(narrowOop* p, oop v);
193 static void encode_store_heap_oop_not_null(oop* p, oop v);
194 static void encode_store_heap_oop(narrowOop* p, oop v);
195 static void encode_store_heap_oop(oop* p, oop v);
196
197 static void release_store_heap_oop(volatile narrowOop* p, narrowOop v);
198 static void release_store_heap_oop(volatile oop* p, oop v);
199
200 static void release_encode_store_heap_oop_not_null(volatile narrowOop* p, oop v);
201 static void release_encode_store_heap_oop_not_null(volatile oop* p, oop v);
202 static void release_encode_store_heap_oop(volatile narrowOop* p, oop v);
203 static void release_encode_store_heap_oop(volatile oop* p, oop v);
204
205 static oop atomic_exchange_oop(oop exchange_value, volatile HeapWord *dest);
206 static oop atomic_compare_exchange_oop(oop exchange_value,
207 volatile HeapWord *dest,
208 oop compare_value);
209
210 // Access to fields in a instanceOop through these methods.
211 oop obj_field(int offset) const;
212 void obj_field_put(int offset, oop value);
213 void obj_field_raw_put(int offset, oop value);
214
215 jbyte byte_field(int offset) const;
216 void byte_field_put(int offset, jbyte contents);
217
218 jchar char_field(int offset) const;
219 void char_field_put(int offset, jchar contents);
220
221 jboolean bool_field(int offset) const;
222 void bool_field_put(int offset, jboolean contents);
223
224 jint int_field(int offset) const;
225 void int_field_put(int offset, jint contents);
226
227 jshort short_field(int offset) const;
228 void short_field_put(int offset, jshort contents);
229
230 jlong long_field(int offset) const;
231 void long_field_put(int offset, jlong contents);
232
233 jfloat float_field(int offset) const;
234 void float_field_put(int offset, jfloat contents);
235
236 jdouble double_field(int offset) const;
237 void double_field_put(int offset, jdouble contents);
238
239 address address_field(int offset) const;
240 void address_field_put(int offset, address contents);
241
242 oop obj_field_acquire(int offset) const;
243 void release_obj_field_put(int offset, oop value);
244
245 jbyte byte_field_acquire(int offset) const;
246 void release_byte_field_put(int offset, jbyte contents);
247
248 jchar char_field_acquire(int offset) const;
249 void release_char_field_put(int offset, jchar contents);
250
251 jboolean bool_field_acquire(int offset) const;
252 void release_bool_field_put(int offset, jboolean contents);
253
254 jint int_field_acquire(int offset) const;
255 void release_int_field_put(int offset, jint contents);
256
257 jshort short_field_acquire(int offset) const;
258 void release_short_field_put(int offset, jshort contents);
259
260 jlong long_field_acquire(int offset) const;
261 void release_long_field_put(int offset, jlong contents);
262
263 jfloat float_field_acquire(int offset) const;
264 void release_float_field_put(int offset, jfloat contents);
265
266 jdouble double_field_acquire(int offset) const;
267 void release_double_field_put(int offset, jdouble contents);
268
269 address address_field_acquire(int offset) const;
270 void release_address_field_put(int offset, address contents);
271
272 // printing functions for VM debugging
273 void print_on(outputStream* st) const; // First level print
274 void print_value_on(outputStream* st) const; // Second level print.
275 void print_address_on(outputStream* st) const; // Address printing
276
277 // printing on default output stream
278 void print();
279 void print_value();
280 void print_address();
281
282 // return the print strings
283 char* print_string();
284 char* print_value_string();
285
286 // verification operations
287 void verify_on(outputStream* st);
288 void verify();
289 void verify_old_oop(oop* p, bool allow_dirty);
290 void verify_old_oop(narrowOop* p, bool allow_dirty);
291
292 // tells whether this oop is partially constructed (gc during class loading)
293 bool partially_loaded();
294 void set_partially_loaded();
295
296 // locking operations
297 bool is_locked() const;
298 bool is_unlocked() const;
299 bool has_bias_pattern() const;
300
301 // asserts
302 bool is_oop(bool ignore_mark_word = false) const;
303 bool is_oop_or_null(bool ignore_mark_word = false) const;
304 #ifndef PRODUCT
305 bool is_unlocked_oop() const;
306 #endif
307
308 // garbage collection
309 bool is_gc_marked() const;
310 // Apply "MarkSweep::mark_and_push" to (the address of) every non-NULL
311 // reference field in "this".
312 void follow_contents(void);
313 void follow_header(void);
314
315 #ifndef SERIALGC
316 // Parallel Scavenge
317 void push_contents(PSPromotionManager* pm);
318
319 // Parallel Old
320 void update_contents(ParCompactionManager* cm);
321 void update_contents(ParCompactionManager* cm,
322 HeapWord* begin_limit,
323 HeapWord* end_limit);
324 void update_contents(ParCompactionManager* cm,
325 klassOop old_klass,
326 HeapWord* begin_limit,
327 HeapWord* end_limit);
328
329 void follow_contents(ParCompactionManager* cm);
330 void follow_header(ParCompactionManager* cm);
331 #endif // SERIALGC
332
333 bool is_perm() const;
334 bool is_perm_or_null() const;
335 bool is_scavengable() const;
336 bool is_shared() const;
337 bool is_shared_readonly() const;
338 bool is_shared_readwrite() const;
339
340 // Forward pointer operations for scavenge
341 bool is_forwarded() const;
342
343 void forward_to(oop p);
344 bool cas_forward_to(oop p, markOop compare);
345
346 #ifndef SERIALGC
347 // Like "forward_to", but inserts the forwarding pointer atomically.
348 // Exactly one thread succeeds in inserting the forwarding pointer, and
349 // this call returns "NULL" for that thread; any other thread has the
350 // value of the forwarding pointer returned and does not modify "this".
351 oop forward_to_atomic(oop p);
352 #endif // SERIALGC
353
354 oop forwardee() const;
355
356 // Age of object during scavenge
357 int age() const;
358 void incr_age();
359
360 // Adjust all pointers in this object to point at it's forwarded location and
361 // return the size of this oop. This is used by the MarkSweep collector.
362 int adjust_pointers();
363 void adjust_header();
364
365 #ifndef SERIALGC
366 // Parallel old
367 void update_header();
368 void update_header(HeapWord* beg_addr, HeapWord* end_addr);
369 #endif // SERIALGC
370
371 // mark-sweep support
372 void follow_body(int begin, int end);
373
374 // Fast access to barrier set
375 static BarrierSet* bs() { return _bs; }
376 static void set_bs(BarrierSet* bs) { _bs = bs; }
377
378 // iterators, returns size of object
379 #define OOP_ITERATE_DECL(OopClosureType, nv_suffix) \
380 int oop_iterate(OopClosureType* blk); \
381 int oop_iterate(OopClosureType* blk, MemRegion mr); // Only in mr.
382
383 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_DECL)
384 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_DECL)
385
386 #ifndef SERIALGC
387
388 #define OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \
389 int oop_iterate_backwards(OopClosureType* blk);
390
391 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_BACKWARDS_DECL)
392 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_BACKWARDS_DECL)
393 #endif
394
395 void oop_iterate_header(OopClosure* blk);
396 void oop_iterate_header(OopClosure* blk, MemRegion mr);
397
398 // identity hash; returns the identity hash key (computes it if necessary)
399 // NOTE with the introduction of UseBiasedLocking that identity_hash() might reach a
400 // safepoint if called on a biased object. Calling code must be aware of that.
401 intptr_t identity_hash();
402 intptr_t slow_identity_hash();
403
404 // marks are forwarded to stack when object is locked
405 bool has_displaced_mark() const;
406 markOop displaced_mark() const;
407 void set_displaced_mark(markOop m);
408
409 // for code generation
410 static int mark_offset_in_bytes() { return offset_of(oopDesc, _mark); }
411 static int klass_offset_in_bytes() { return offset_of(oopDesc, _metadata._klass); }
412 static int klass_gap_offset_in_bytes();
413 };
414
415 #endif // SHARE_VM_OOPS_OOP_HPP