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
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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_addr();
87 narrowKlass* compressed_klass_addr();
88
89 void set_klass(Klass* k);
90
91 // For klass field compression
92 int klass_gap() const;
93 void set_klass_gap(int z);
94 // For when the klass pointer is being used as a linked list "next" field.
95 void set_klass_to_list_ptr(oop k);
96 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 bool is_a(Klass* k) const;
103
104 // Returns the actual oop size of the object
105 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 int size_given_klass(Klass* klass);
110
111 // type test operations (inlined in oop.inline.h)
112 bool is_instance() const;
113 bool is_instanceMirror() const;
114 bool is_instanceClassLoader() const;
115 bool is_instanceRef() const;
116 bool is_array() const;
117 bool is_objArray() const;
118 bool is_typeArray() const;
119
120 // type test operations that doesn't require inclusion of oop.inline.hpp.
121 bool is_instance_noinline() const;
122 bool is_instanceMirror_noinline() const;
123 bool is_instanceClassLoader_noline() const;
124 bool is_instanceRef_noline() const;
125 bool is_array_noinline() const;
126 bool is_objArray_noinline() const;
127 bool is_typeArray_noinline() const;
128
129 private:
130 // field addresses in oop
131 void* field_base(int offset) const;
132
133 jbyte* byte_field_addr(int offset) const;
134 jchar* char_field_addr(int offset) const;
135 jboolean* bool_field_addr(int offset) const;
136 jint* int_field_addr(int offset) const;
137 jshort* short_field_addr(int offset) const;
138 jlong* long_field_addr(int offset) const;
139 jfloat* float_field_addr(int offset) const;
140 jdouble* double_field_addr(int offset) const;
141 Metadata** metadata_field_addr(int offset) const;
142
143 public:
144 // Need this as public for garbage collection.
145 template <class T> T* obj_field_addr(int offset) const;
146
147 // Needed for javaClasses
148 address* address_field_addr(int offset) const;
149
150 static bool is_null(oop obj);
151 static bool is_null(narrowOop obj);
152 static bool is_null(Klass* obj);
153
154 // Decode an oop pointer from a narrowOop if compressed.
155 // These are overloaded for oop and narrowOop as are the other functions
156 // below so that they can be called in template functions.
157 static oop decode_heap_oop_not_null(oop v);
158 static oop decode_heap_oop_not_null(narrowOop v);
159 static oop decode_heap_oop(oop v);
160 static oop decode_heap_oop(narrowOop v);
161
162 // Encode an oop pointer to a narrow oop. The or_null versions accept
163 // null oop pointer, others do not in order to eliminate the
164 // null checking branches.
165 static narrowOop encode_heap_oop_not_null(oop v);
166 static narrowOop encode_heap_oop(oop v);
167
168 // Load an oop out of the Java heap
169 static narrowOop load_heap_oop(narrowOop* p);
170 static oop load_heap_oop(oop* p);
171
172 // Load an oop out of Java heap and decode it to an uncompressed oop.
173 static oop load_decode_heap_oop_not_null(narrowOop* p);
174 static oop load_decode_heap_oop_not_null(oop* p);
175 static oop load_decode_heap_oop(narrowOop* p);
176 static oop load_decode_heap_oop(oop* p);
177
178 // Store an oop into the heap.
179 static void store_heap_oop(narrowOop* p, narrowOop v);
180 static void store_heap_oop(oop* p, oop v);
181
182 // Encode oop if UseCompressedOops and store into the heap.
183 static void encode_store_heap_oop_not_null(narrowOop* p, oop v);
184 static void encode_store_heap_oop_not_null(oop* p, oop v);
185 static void encode_store_heap_oop(narrowOop* p, oop v);
186 static void encode_store_heap_oop(oop* p, oop v);
187
188 static void release_store_heap_oop(volatile narrowOop* p, narrowOop v);
189 static void release_store_heap_oop(volatile oop* p, oop v);
190
191 static void release_encode_store_heap_oop_not_null(volatile narrowOop* p, oop v);
192 static void release_encode_store_heap_oop_not_null(volatile oop* p, oop v);
193 static void release_encode_store_heap_oop(volatile narrowOop* p, oop v);
194 static void release_encode_store_heap_oop(volatile oop* p, oop v);
195
196 static oop atomic_exchange_oop(oop exchange_value, volatile HeapWord *dest);
197 static oop atomic_compare_exchange_oop(oop exchange_value,
198 volatile HeapWord *dest,
199 oop compare_value,
200 bool prebarrier = false);
201
202 // Access to fields in a instanceOop through these methods.
203 oop obj_field(int offset) const;
204 volatile oop obj_field_volatile(int offset) const;
205 void obj_field_put(int offset, oop value);
206 void obj_field_put_raw(int offset, oop value);
207 void obj_field_put_volatile(int offset, oop value);
208
209 Metadata* metadata_field(int offset) const;
210 void metadata_field_put(int offset, Metadata* value);
211
212 jbyte byte_field(int offset) const;
213 void byte_field_put(int offset, jbyte contents);
214
215 jchar char_field(int offset) const;
216 void char_field_put(int offset, jchar contents);
217
218 jboolean bool_field(int offset) const;
219 void bool_field_put(int offset, jboolean contents);
220
221 jint int_field(int offset) const;
222 void int_field_put(int offset, jint contents);
223
224 jshort short_field(int offset) const;
225 void short_field_put(int offset, jshort contents);
226
227 jlong long_field(int offset) const;
228 void long_field_put(int offset, jlong contents);
229
230 jfloat float_field(int offset) const;
231 void float_field_put(int offset, jfloat contents);
232
233 jdouble double_field(int offset) const;
234 void double_field_put(int offset, jdouble contents);
235
236 address address_field(int offset) const;
237 void address_field_put(int offset, address contents);
238
239 oop obj_field_acquire(int offset) const;
240 void release_obj_field_put(int offset, oop value);
241
242 jbyte byte_field_acquire(int offset) const;
243 void release_byte_field_put(int offset, jbyte contents);
244
245 jchar char_field_acquire(int offset) const;
246 void release_char_field_put(int offset, jchar contents);
247
248 jboolean bool_field_acquire(int offset) const;
249 void release_bool_field_put(int offset, jboolean contents);
250
251 jint int_field_acquire(int offset) const;
252 void release_int_field_put(int offset, jint contents);
253
254 jshort short_field_acquire(int offset) const;
255 void release_short_field_put(int offset, jshort contents);
256
257 jlong long_field_acquire(int offset) const;
258 void release_long_field_put(int offset, jlong contents);
259
260 jfloat float_field_acquire(int offset) const;
261 void release_float_field_put(int offset, jfloat contents);
262
263 jdouble double_field_acquire(int offset) const;
264 void release_double_field_put(int offset, jdouble contents);
265
266 address address_field_acquire(int offset) const;
267 void release_address_field_put(int offset, address contents);
268
269 // printing functions for VM debugging
270 void print_on(outputStream* st) const; // First level print
271 void print_value_on(outputStream* st) const; // Second level print.
272 void print_address_on(outputStream* st) const; // Address printing
273
274 // printing on default output stream
275 void print();
276 void print_value();
277 void print_address();
278
279 // return the print strings
280 char* print_string();
281 char* print_value_string();
282
283 // verification operations
284 void verify_on(outputStream* st);
285 void verify();
286
287 // locking operations
288 bool is_locked() const;
289 bool is_unlocked() const;
290 bool has_bias_pattern() const;
291
292 // asserts
293 bool is_oop(bool ignore_mark_word = false) const;
294 bool is_oop_or_null(bool ignore_mark_word = false) const;
295 #ifndef PRODUCT
296 bool is_unlocked_oop() const;
297 #endif
298
299 // garbage collection
300 bool is_gc_marked() const;
301 // Apply "MarkSweep::mark_and_push" to (the address of) every non-NULL
302 // reference field in "this".
303 void follow_contents(void);
304
305 #if INCLUDE_ALL_GCS
306 // Parallel Scavenge
307 void push_contents(PSPromotionManager* pm);
308
309 // Parallel Old
310 void update_contents(ParCompactionManager* cm);
311
312 void follow_contents(ParCompactionManager* cm);
313 #endif // INCLUDE_ALL_GCS
314
315 bool is_scavengable() const;
316
317 // Forward pointer operations for scavenge
318 bool is_forwarded() const;
319
320 void forward_to(oop p);
321 bool cas_forward_to(oop p, markOop compare);
322
323 #if INCLUDE_ALL_GCS
324 // Like "forward_to", but inserts the forwarding pointer atomically.
325 // Exactly one thread succeeds in inserting the forwarding pointer, and
326 // this call returns "NULL" for that thread; any other thread has the
327 // value of the forwarding pointer returned and does not modify "this".
328 oop forward_to_atomic(oop p);
329 #endif // INCLUDE_ALL_GCS
330
331 oop forwardee() const;
332
333 // Age of object during scavenge
334 uint age() const;
335 void incr_age();
336
337 // Adjust all pointers in this object to point at it's forwarded location and
338 // return the size of this oop. This is used by the MarkSweep collector.
339 int adjust_pointers();
340
341 // mark-sweep support
342 void follow_body(int begin, int end);
343
344 // Fast access to barrier set
345 static BarrierSet* bs() { return _bs; }
346 static void set_bs(BarrierSet* bs) { _bs = bs; }
347
348 // iterators, returns size of object
349 #define OOP_ITERATE_DECL(OopClosureType, nv_suffix) \
350 int oop_iterate(OopClosureType* blk); \
351 int oop_iterate(OopClosureType* blk, MemRegion mr); // Only in mr.
352
353 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_DECL)
354 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_DECL)
355
356 #if INCLUDE_ALL_GCS
357
358 #define OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \
359 int oop_iterate_backwards(OopClosureType* blk);
360
361 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_BACKWARDS_DECL)
362 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_BACKWARDS_DECL)
363 #endif
364
365 int oop_iterate_no_header(OopClosure* bk);
366 int oop_iterate_no_header(OopClosure* bk, MemRegion mr);
367
368 // identity hash; returns the identity hash key (computes it if necessary)
369 // NOTE with the introduction of UseBiasedLocking that identity_hash() might reach a
370 // safepoint if called on a biased object. Calling code must be aware of that.
371 intptr_t identity_hash();
372 intptr_t slow_identity_hash();
373
374 // Alternate hashing code if string table is rehashed
375 unsigned int new_hash(juint seed);
376
377 // marks are forwarded to stack when object is locked
378 bool has_displaced_mark() const;
379 markOop displaced_mark() const;
380 void set_displaced_mark(markOop m);
381
382 static bool has_klass_gap();
383
384 // for code generation
385 static int mark_offset_in_bytes() { return offset_of(oopDesc, _mark); }
386 static int klass_offset_in_bytes() { return offset_of(oopDesc, _metadata._klass); }
387 static int klass_gap_offset_in_bytes() {
388 assert(has_klass_gap(), "only applicable to compressed klass pointers");
389 return klass_offset_in_bytes() + sizeof(narrowKlass);
390 }
391 };
392
393 #endif // SHARE_VM_OOPS_OOP_HPP