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.
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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
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.inline.hpp"
31 #include "oops/metadata.hpp"
32 #include "utilities/macros.hpp"
33 #include "utilities/top.hpp"
34 #include "utilities/templateIdioms.hpp"
35
36 // oopDesc is the top baseclass for objects classes. The {name}Desc classes describe
37 // the format of Java objects so the fields can be accessed from C++.
38 // oopDesc is abstract.
39 // (see oopHierarchy for complete oop class hierarchy)
40 //
41 // no virtual functions allowed
42
43 // store into oop with store check
44 template <class T> void oop_store(T* p, oop v);
45 template <class T> void oop_store(volatile T* p, oop v);
46
47 extern bool always_do_update_barrier;
48
49 // Forward declarations.
50 class OopClosure;
51 class ScanClosure;
52 class FastScanClosure;
53 class FilteringClosure;
54 class BarrierSet;
55 class CMSIsAliveClosure;
56
57 class PSPromotionManager;
58 class ParCompactionManager;
59
60 class oopDesc {
61 friend class VMStructs;
62 private:
63 volatile markOop _mark;
64 union _metadata {
65 Klass* _klass;
66 narrowKlass _compressed_klass;
67 } _metadata;
68
69 // Fast access to barrier set. Must be initialized.
70 static BarrierSet* _bs;
71
72 public:
73 markOop mark() const { return _mark; }
74 markOop* mark_addr() const { return (markOop*) &_mark; }
75
76 void set_mark(volatile markOop m) { _mark = m; }
77
78 void release_set_mark(markOop m);
79 markOop cas_set_mark(markOop new_mark, markOop old_mark);
80
81 // Used only to re-initialize the mark word (e.g., of promoted
82 // objects during a GC) -- requires a valid klass pointer
83 void init_mark();
84
85 Klass* klass() const;
86 Klass* klass_or_null() const volatile;
87 Klass** klass_addr();
88 narrowKlass* compressed_klass_addr();
89
90 void set_klass(Klass* k);
91
92 // For klass field compression
93 int klass_gap() const;
94 void set_klass_gap(int z);
95 // For when the klass pointer is being used as a linked list "next" field.
96 void set_klass_to_list_ptr(oop k);
97 oop list_ptr_from_klass();
98
99 // size of object header, aligned to platform wordSize
100 static int header_size() { return sizeof(oopDesc)/HeapWordSize; }
101
102 // Returns whether this is an instance of k or an instance of a subclass of k
103 bool is_a(Klass* k) const;
104
105 // Returns the actual oop size of the object
106 int size();
107
108 // Sometimes (for complicated concurrency-related reasons), it is useful
109 // to be able to figure out the size of an object knowing its klass.
110 int size_given_klass(Klass* klass);
111
112 // type test operations (inlined in oop.inline.h)
113 bool is_instance() const;
114 bool is_instanceMirror() const;
115 bool is_instanceClassLoader() const;
116 bool is_instanceRef() const;
117 bool is_array() const;
118 bool is_objArray() const;
119 bool is_typeArray() const;
120
121 private:
122 // field addresses in oop
123 void* field_base(int offset) const;
124
125 jbyte* byte_field_addr(int offset) const;
126 jchar* char_field_addr(int offset) const;
127 jboolean* bool_field_addr(int offset) const;
128 jint* int_field_addr(int offset) const;
129 jshort* short_field_addr(int offset) const;
130 jlong* long_field_addr(int offset) const;
131 jfloat* float_field_addr(int offset) const;
132 jdouble* double_field_addr(int offset) const;
133 Metadata** metadata_field_addr(int offset) const;
134
135 public:
136 // Need this as public for garbage collection.
137 template <class T> T* obj_field_addr(int offset) const;
138
139 // Needed for javaClasses
140 address* address_field_addr(int offset) const;
141
142 static bool is_null(oop obj);
143 static bool is_null(narrowOop obj);
144 static bool is_null(Klass* obj);
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 oop decode_heap_oop_not_null(oop v);
150 static oop decode_heap_oop_not_null(narrowOop v);
151 static oop decode_heap_oop(oop v);
152 static 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 narrowOop encode_heap_oop_not_null(oop v);
158 static narrowOop encode_heap_oop(oop v);
159
160 // Load an oop out of the Java heap
161 static narrowOop load_heap_oop(narrowOop* p);
162 static oop load_heap_oop(oop* p);
163
164 // Load an oop out of Java heap and decode it to an uncompressed oop.
165 static oop load_decode_heap_oop_not_null(narrowOop* p);
166 static oop load_decode_heap_oop_not_null(oop* p);
167 static oop load_decode_heap_oop(narrowOop* p);
168 static oop load_decode_heap_oop(oop* p);
169
170 // Store an oop into the heap.
171 static void store_heap_oop(narrowOop* p, narrowOop v);
172 static void store_heap_oop(oop* p, oop v);
173
174 // Encode oop if UseCompressedOops and store into the heap.
175 static void encode_store_heap_oop_not_null(narrowOop* p, oop v);
176 static void encode_store_heap_oop_not_null(oop* p, oop v);
177 static void encode_store_heap_oop(narrowOop* p, oop v);
178 static void encode_store_heap_oop(oop* p, oop v);
179
180 static void release_store_heap_oop(volatile narrowOop* p, narrowOop v);
181 static void release_store_heap_oop(volatile oop* p, oop v);
182
183 static void release_encode_store_heap_oop_not_null(volatile narrowOop* p, oop v);
184 static void release_encode_store_heap_oop_not_null(volatile oop* p, oop v);
185 static void release_encode_store_heap_oop(volatile narrowOop* p, oop v);
186 static void release_encode_store_heap_oop(volatile oop* p, oop v);
187
188 static oop atomic_exchange_oop(oop exchange_value, volatile HeapWord *dest);
189 static oop atomic_compare_exchange_oop(oop exchange_value,
190 volatile HeapWord *dest,
191 oop compare_value,
192 bool prebarrier = false);
193
194 // Access to fields in a instanceOop through these methods.
195 oop obj_field(int offset) const;
196 volatile oop obj_field_volatile(int offset) const;
197 void obj_field_put(int offset, oop value);
198 void obj_field_put_raw(int offset, oop value);
199 void obj_field_put_volatile(int offset, oop value);
200
201 Metadata* metadata_field(int offset) const;
202 void metadata_field_put(int offset, Metadata* value);
203
204 jbyte byte_field(int offset) const;
205 void byte_field_put(int offset, jbyte contents);
206
207 jchar char_field(int offset) const;
208 void char_field_put(int offset, jchar contents);
209
210 jboolean bool_field(int offset) const;
211 void bool_field_put(int offset, jboolean contents);
212
213 jint int_field(int offset) const;
214 void int_field_put(int offset, jint contents);
215
216 jshort short_field(int offset) const;
217 void short_field_put(int offset, jshort contents);
218
219 jlong long_field(int offset) const;
220 void long_field_put(int offset, jlong contents);
221
222 jfloat float_field(int offset) const;
223 void float_field_put(int offset, jfloat contents);
224
225 jdouble double_field(int offset) const;
226 void double_field_put(int offset, jdouble contents);
227
228 address address_field(int offset) const;
229 void address_field_put(int offset, address contents);
230
231 oop obj_field_acquire(int offset) const;
232 void release_obj_field_put(int offset, oop value);
233
234 jbyte byte_field_acquire(int offset) const;
235 void release_byte_field_put(int offset, jbyte contents);
236
237 jchar char_field_acquire(int offset) const;
238 void release_char_field_put(int offset, jchar contents);
239
240 jboolean bool_field_acquire(int offset) const;
241 void release_bool_field_put(int offset, jboolean contents);
242
243 jint int_field_acquire(int offset) const;
244 void release_int_field_put(int offset, jint contents);
245
246 jshort short_field_acquire(int offset) const;
247 void release_short_field_put(int offset, jshort contents);
248
249 jlong long_field_acquire(int offset) const;
250 void release_long_field_put(int offset, jlong contents);
251
252 jfloat float_field_acquire(int offset) const;
253 void release_float_field_put(int offset, jfloat contents);
254
255 jdouble double_field_acquire(int offset) const;
256 void release_double_field_put(int offset, jdouble contents);
257
258 address address_field_acquire(int offset) const;
259 void release_address_field_put(int offset, address contents);
260
261 // printing functions for VM debugging
262 void print_on(outputStream* st) const; // First level print
263 void print_value_on(outputStream* st) const; // Second level print.
264 void print_address_on(outputStream* st) const; // Address printing
265
266 // printing on default output stream
267 void print();
268 void print_value();
269 void print_address();
270
271 // return the print strings
272 char* print_string();
273 char* print_value_string();
274
275 // verification operations
276 void verify_on(outputStream* st);
277 void verify();
278
279 // locking operations
280 bool is_locked() const;
281 bool is_unlocked() const;
282 bool has_bias_pattern() const;
283
284 // asserts
285 bool is_oop(bool ignore_mark_word = false) const;
286 bool is_oop_or_null(bool ignore_mark_word = false) const;
287 #ifndef PRODUCT
288 bool is_unlocked_oop() const;
289 #endif
290
291 // garbage collection
292 bool is_gc_marked() const;
293 // Apply "MarkSweep::mark_and_push" to (the address of) every non-NULL
294 // reference field in "this".
295 void follow_contents(void);
296
297 #if INCLUDE_ALL_GCS
298 // Parallel Scavenge
299 void push_contents(PSPromotionManager* pm);
300
301 // Parallel Old
302 void update_contents(ParCompactionManager* cm);
303
304 void follow_contents(ParCompactionManager* cm);
305 #endif // INCLUDE_ALL_GCS
306
307 bool is_scavengable() const;
308
309 // Forward pointer operations for scavenge
310 bool is_forwarded() const;
311
312 void forward_to(oop p);
313 bool cas_forward_to(oop p, markOop compare);
314
315 #if INCLUDE_ALL_GCS
316 // Like "forward_to", but inserts the forwarding pointer atomically.
317 // Exactly one thread succeeds in inserting the forwarding pointer, and
318 // this call returns "NULL" for that thread; any other thread has the
319 // value of the forwarding pointer returned and does not modify "this".
320 oop forward_to_atomic(oop p);
321 #endif // INCLUDE_ALL_GCS
322
323 oop forwardee() const;
324
325 // Age of object during scavenge
326 uint age() const;
327 void incr_age();
328
329 // Adjust all pointers in this object to point at it's forwarded location and
330 // return the size of this oop. This is used by the MarkSweep collector.
331 int adjust_pointers();
332
333 // mark-sweep support
334 void follow_body(int begin, int end);
335
336 // Fast access to barrier set
337 static BarrierSet* bs() { return _bs; }
338 static void set_bs(BarrierSet* bs) { _bs = bs; }
339
340 private:
341 // Dispatch member functions to oop closures
342
343 template <class OopClosureType>
344 typename enable_if<is_kind_of<ExtendedOopClosure, OopClosureType>::value, void>::type
345 do_metadata_if_applicable(OopClosureType *cl);
346
347 template <class OopClosureType>
348 typename enable_if<!is_kind_of<ExtendedOopClosure, OopClosureType>::value, void>::type
349 do_metadata_if_applicable(OopClosureType *cl);
350
351 template <class OopClosureType>
352 int oop_iterate_dispatch_tag(OopClosureType *blk, DispatchTag tag);
353
354 template <class OopClosureType>
355 int oop_iterate_internal(OopClosureType *blk);
356
357 public:
358 template <class OopClosureType>
359 typename enable_if<is_kind_of<ExtendedOopClosure, OopClosureType>::value, int>::type
360 oop_iterate(OopClosureType *blk);
361
362 // iterators, returns size of object
363
364 #define OOP_ITERATE_DECL(OopClosureType, nv_suffix) \
365 int oop_iterate(OopClosureType* blk); \
366 int oop_iterate(OopClosureType* blk, MemRegion mr); // Only in mr.
367
368 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_DECL)
369 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_DECL)
370
371 #if INCLUDE_ALL_GCS
372
373 #define OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \
374 int oop_iterate_backwards(OopClosureType* blk);
375
376 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_BACKWARDS_DECL)
377 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_BACKWARDS_DECL)
378 #endif
379
380 template <class OopClosureType>
381 typename enable_if<is_kind_of<OopClosure, OopClosureType>::value, int>::type
382 oop_iterate_no_header(OopClosureType* bk);
383
384 int oop_iterate_no_header(OopClosure* bk, MemRegion mr);
385
386 // identity hash; returns the identity hash key (computes it if necessary)
387 // NOTE with the introduction of UseBiasedLocking that identity_hash() might reach a
388 // safepoint if called on a biased object. Calling code must be aware of that.
389 intptr_t identity_hash();
390 intptr_t slow_identity_hash();
391
392 // Alternate hashing code if string table is rehashed
393 unsigned int new_hash(juint seed);
394
395 // marks are forwarded to stack when object is locked
396 bool has_displaced_mark() const;
397 markOop displaced_mark() const;
398 void set_displaced_mark(markOop m);
399
400 // for code generation
401 static int mark_offset_in_bytes() { return offset_of(oopDesc, _mark); }
402 static int klass_offset_in_bytes() { return offset_of(oopDesc, _metadata._klass); }
403 static int klass_gap_offset_in_bytes();
404 };
405
406 #endif // SHARE_VM_OOPS_OOP_HPP