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
21 * questions.
22 *
23 */
24
25 #ifndef SHARE_VM_OOPS_OOP_HPP
26 #define SHARE_VM_OOPS_OOP_HPP
27
28 #include "memory/barrierSet.hpp"
29 #include "memory/iterator.hpp"
30 #include "memory/memRegion.hpp"
31 #include "memory/specialized_oop_closures.hpp"
32 #include "oops/metadata.hpp"
33 #include "utilities/macros.hpp"
34 #include "utilities/top.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 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 {
73 oop p = bs()->read_barrier((oop) this);
74 return p->_mark;
75 }
76 markOop* mark_addr() const { return (markOop*) &_mark; }
77
78 void set_mark(volatile markOop m) {
79 oop p = bs()->write_barrier(this);
80 p->_mark = m;
81 }
82
83 void set_mark_raw(volatile markOop m) {
84 _mark = m;
85 }
86
87 void release_set_mark(markOop m);
88 markOop cas_set_mark(markOop new_mark, markOop old_mark);
89
90 // Used only to re-initialize the mark word (e.g., of promoted
91 // objects during a GC) -- requires a valid klass pointer
92 void init_mark();
93
94 Klass* klass() const;
95 Klass* klass_or_null() const volatile;
96 Klass** klass_addr();
97 narrowKlass* compressed_klass_addr();
98
99 void set_klass(Klass* k);
100
101 // For klass field compression
102 int klass_gap() const;
103 void set_klass_gap(int z);
104 // For when the klass pointer is being used as a linked list "next" field.
105 void set_klass_to_list_ptr(oop k);
106 oop list_ptr_from_klass();
107
108 // size of object header, aligned to platform wordSize
109 static int header_size() { return sizeof(oopDesc)/HeapWordSize; }
110
111 // Returns whether this is an instance of k or an instance of a subclass of k
112 bool is_a(Klass* k) const;
113
114 // Returns the actual oop size of the object
115 int size();
116
117 // Sometimes (for complicated concurrency-related reasons), it is useful
118 // to be able to figure out the size of an object knowing its klass.
119 int size_given_klass(Klass* klass);
120
121 // type test operations (inlined in oop.inline.h)
122 bool is_instance() const;
123 bool is_instanceMirror() const;
124 bool is_instanceClassLoader() const;
125 bool is_instanceRef() const;
126 bool is_array() const;
127 bool is_objArray() const;
128 bool is_typeArray() const;
129
130 private:
131 // field addresses in oop
132 void* field_base(int offset) const;
133
134 jbyte* byte_field_addr(int offset) const;
135 jchar* char_field_addr(int offset) const;
136 jboolean* bool_field_addr(int offset) const;
137 jint* int_field_addr(int offset) const;
138 jshort* short_field_addr(int offset) const;
139 jlong* long_field_addr(int offset) const;
140 jfloat* float_field_addr(int offset) const;
141 jdouble* double_field_addr(int offset) const;
142 Metadata** metadata_field_addr(int offset) const;
143
144 public:
145 // Need this as public for garbage collection.
146 template <class T> T* obj_field_addr(int offset) const;
147
148 // Needed for javaClasses
149 address* address_field_addr(int offset) const;
150
151 static bool is_null(oop obj);
152 static bool is_null(narrowOop obj);
153 static bool is_null(Klass* obj);
154
155 inline static bool equals(oop o1, oop o2) {
156 return bs()->obj_equals(o1, o2);
157 }
158
159 inline static bool equals(narrowOop o1, narrowOop o2) {
160 return bs()->obj_equals(o1, o2);
161 }
162
163 inline static bool unsafe_equals(oop o1, oop o2) {
164 #ifdef CHECK_UNHANDLED_OOPS
165 return o1.obj() == o2.obj();
166 #else
167 return o1 == o2;
168 #endif
169 }
170
171 inline static bool unsafe_equals(narrowOop o1, narrowOop o2) {
172 return o1 == o2;
173 }
174
175 // Decode an oop pointer from a narrowOop if compressed.
176 // These are overloaded for oop and narrowOop as are the other functions
177 // below so that they can be called in template functions.
178 static oop decode_heap_oop_not_null(oop v);
179 static oop decode_heap_oop_not_null(narrowOop v);
180 static oop decode_heap_oop(oop v);
181 static oop decode_heap_oop(narrowOop v);
182
183 // Encode an oop pointer to a narrow oop. The or_null versions accept
184 // null oop pointer, others do not in order to eliminate the
185 // null checking branches.
186 static narrowOop encode_heap_oop_not_null(oop v);
187 static narrowOop encode_heap_oop(oop v);
188
189 // Load an oop out of the Java heap
190 static narrowOop load_heap_oop(narrowOop* p);
191 static oop load_heap_oop(oop* p);
192
193 // Load an oop out of Java heap and decode it to an uncompressed oop.
194 static oop load_decode_heap_oop_not_null(narrowOop* p);
195 static oop load_decode_heap_oop_not_null(oop* p);
196 static oop load_decode_heap_oop(narrowOop* p);
197 static oop load_decode_heap_oop(oop* p);
198
199 // Store an oop into the heap.
200 static void store_heap_oop(narrowOop* p, narrowOop v);
201 static void store_heap_oop(oop* p, oop v);
202
203 // Encode oop if UseCompressedOops and store into the heap.
204 static void encode_store_heap_oop_not_null(narrowOop* p, oop v);
205 static void encode_store_heap_oop_not_null(oop* p, oop v);
206 static void encode_store_heap_oop(narrowOop* p, oop v);
207 static void encode_store_heap_oop(oop* p, oop v);
208
209 static void release_store_heap_oop(volatile narrowOop* p, narrowOop v);
210 static void release_store_heap_oop(volatile oop* p, oop v);
211
212 static void release_encode_store_heap_oop_not_null(volatile narrowOop* p, oop v);
213 static void release_encode_store_heap_oop_not_null(volatile oop* p, oop v);
214 static void release_encode_store_heap_oop(volatile narrowOop* p, oop v);
215 static void release_encode_store_heap_oop(volatile oop* p, oop v);
216
217 static oop atomic_exchange_oop(oop exchange_value, volatile HeapWord *dest);
218 static oop atomic_compare_exchange_oop(oop exchange_value,
219 volatile HeapWord *dest,
220 oop compare_value,
221 bool prebarrier = false);
222
223 // Access to fields in a instanceOop through these methods.
224 oop obj_field(int offset) const;
225 volatile oop obj_field_volatile(int offset) const;
226 void obj_field_put(int offset, oop value);
227 void obj_field_put_raw(int offset, oop value);
228 void obj_field_put_volatile(int offset, oop value);
229
230 Metadata* metadata_field(int offset) const;
231 void metadata_field_put(int offset, Metadata* value);
232
233 jbyte byte_field(int offset) const;
234 void byte_field_put(int offset, jbyte contents);
235
236 jchar char_field(int offset) const;
237 void char_field_put(int offset, jchar contents);
238
239 jboolean bool_field(int offset) const;
240 void bool_field_put(int offset, jboolean contents);
241
242 jint int_field(int offset) const;
243 void int_field_put(int offset, jint contents);
244 void int_field_put_raw(int offset, jint contents);
245
246 jshort short_field(int offset) const;
247 void short_field_put(int offset, jshort contents);
248
249 jlong long_field(int offset) const;
250 void long_field_put(int offset, jlong contents);
251
252 jfloat float_field(int offset) const;
253 void float_field_put(int offset, jfloat contents);
254
255 jdouble double_field(int offset) const;
256 void double_field_put(int offset, jdouble contents);
257
258 address address_field(int offset) const;
259 void address_field_put(int offset, address contents);
260
261 oop obj_field_acquire(int offset) const;
262 void release_obj_field_put(int offset, oop value);
263
264 jbyte byte_field_acquire(int offset) const;
265 void release_byte_field_put(int offset, jbyte contents);
266
267 jchar char_field_acquire(int offset) const;
268 void release_char_field_put(int offset, jchar contents);
269
270 jboolean bool_field_acquire(int offset) const;
271 void release_bool_field_put(int offset, jboolean contents);
272
273 jint int_field_acquire(int offset) const;
274 void release_int_field_put(int offset, jint contents);
275
276 jshort short_field_acquire(int offset) const;
277 void release_short_field_put(int offset, jshort contents);
278
279 jlong long_field_acquire(int offset) const;
280 void release_long_field_put(int offset, jlong contents);
281
282 jfloat float_field_acquire(int offset) const;
283 void release_float_field_put(int offset, jfloat contents);
284
285 jdouble double_field_acquire(int offset) const;
286 void release_double_field_put(int offset, jdouble contents);
287
288 address address_field_acquire(int offset) const;
289 void release_address_field_put(int offset, address contents);
290
291 // printing functions for VM debugging
292 void print_on(outputStream* st) const; // First level print
293 void print_value_on(outputStream* st) const; // Second level print.
294 void print_address_on(outputStream* st) const; // Address printing
295
296 // printing on default output stream
297 void print();
298 void print_value();
299 void print_address();
300
301 // return the print strings
302 char* print_string();
303 char* print_value_string();
304
305 // verification operations
306 void verify_on(outputStream* st);
307 void verify();
308
309 // locking operations
310 bool is_locked() const;
311 bool is_unlocked() const;
312 bool has_bias_pattern() const;
313
314 // asserts
315 bool is_oop(bool ignore_mark_word = false) const;
316 bool is_oop_or_null(bool ignore_mark_word = false) const;
317 #ifndef PRODUCT
318 bool is_unlocked_oop() const;
319 #endif
320
321 // garbage collection
322 bool is_gc_marked() const;
323 // Apply "MarkSweep::mark_and_push" to (the address of) every non-NULL
324 // reference field in "this".
325 void follow_contents(void);
326
327 #if INCLUDE_ALL_GCS
328 // Parallel Scavenge
329 void push_contents(PSPromotionManager* pm);
330
331 // Parallel Old
332 void update_contents(ParCompactionManager* cm);
333
334 void follow_contents(ParCompactionManager* cm);
335 #endif // INCLUDE_ALL_GCS
336
337 bool is_scavengable() const;
338
339 // Forward pointer operations for scavenge
340 bool is_forwarded() const;
341
342 void forward_to(oop p);
343 bool cas_forward_to(oop p, markOop compare);
344
345 #if INCLUDE_ALL_GCS
346 // Like "forward_to", but inserts the forwarding pointer atomically.
347 // Exactly one thread succeeds in inserting the forwarding pointer, and
348 // this call returns "NULL" for that thread; any other thread has the
349 // value of the forwarding pointer returned and does not modify "this".
350 oop forward_to_atomic(oop p);
351 #endif // INCLUDE_ALL_GCS
352
353 oop forwardee() const;
354
355 // Age of object during scavenge
356 uint age() const;
357 void incr_age();
358
359 // Adjust all pointers in this object to point at it's forwarded location and
360 // return the size of this oop. This is used by the MarkSweep collector.
361 int adjust_pointers();
362
363 // mark-sweep support
364 void follow_body(int begin, int end);
365
366 // Fast access to barrier set
367 static BarrierSet* bs() { return _bs; }
368 static void set_bs(BarrierSet* bs) { _bs = bs; }
369
370 // iterators, returns size of object
371 #define OOP_ITERATE_DECL(OopClosureType, nv_suffix) \
372 int oop_iterate(OopClosureType* blk); \
373 int oop_iterate(OopClosureType* blk, MemRegion mr); // Only in mr.
374
375 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_DECL)
376 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_DECL)
377
378 #if INCLUDE_ALL_GCS
379
380 #define OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \
381 int oop_iterate_backwards(OopClosureType* blk);
382
383 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_BACKWARDS_DECL)
384 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_BACKWARDS_DECL)
385 #endif
386
387 int oop_iterate_no_header(OopClosure* bk);
388 int oop_iterate_no_header(OopClosure* bk, MemRegion mr);
389
390 // identity hash; returns the identity hash key (computes it if necessary)
391 // NOTE with the introduction of UseBiasedLocking that identity_hash() might reach a
392 // safepoint if called on a biased object. Calling code must be aware of that.
393 intptr_t identity_hash();
394 intptr_t slow_identity_hash();
395
396 // Alternate hashing code if string table is rehashed
397 unsigned int new_hash(juint seed);
398
399 // marks are forwarded to stack when object is locked
400 bool has_displaced_mark() const;
401 markOop displaced_mark() const;
402 void set_displaced_mark(markOop m);
403
404 // for code generation
405 static int mark_offset_in_bytes() { return offset_of(oopDesc, _mark); }
406 static int klass_offset_in_bytes() { return offset_of(oopDesc, _metadata._klass); }
407 static int klass_gap_offset_in_bytes();
408 };
409
410 #endif // SHARE_VM_OOPS_OOP_HPP