1 /*
2 * Copyright (c) 1997, 2011, 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/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 enum ConcSafeType {
75 IsUnsafeConc = false,
76 IsSafeConc = true
77 };
78
79 markOop mark() const { return _mark; }
80 markOop* mark_addr() const { return (markOop*) &_mark; }
81
82 void set_mark(volatile markOop m) { _mark = m; }
83
84 void release_set_mark(markOop m);
85 markOop cas_set_mark(markOop new_mark, markOop old_mark);
86
87 // Used only to re-initialize the mark word (e.g., of promoted
88 // objects during a GC) -- requires a valid klass pointer
89 void init_mark();
90
91 klassOop klass() const;
92 klassOop klass_or_null() const volatile;
93 oop* klass_addr();
94 narrowOop* compressed_klass_addr();
95
96 void set_klass(klassOop k);
97
98 // For klass field compression
99 int klass_gap() const;
100 void set_klass_gap(int z);
101 // For when the klass pointer is being used as a linked list "next" field.
102 void set_klass_to_list_ptr(oop k);
103
104 // size of object header, aligned to platform wordSize
105 static int header_size() { return sizeof(oopDesc)/HeapWordSize; }
106
107 Klass* blueprint() const;
108
109 // Returns whether this is an instance of k or an instance of a subclass of k
110 bool is_a(klassOop k) const;
111
112 // Returns the actual oop size of the object
113 int size();
114
115 // Sometimes (for complicated concurrency-related reasons), it is useful
116 // to be able to figure out the size of an object knowing its klass.
117 int size_given_klass(Klass* klass);
118
119 // Some perm gen objects are not parseble immediately after
120 // installation of their klass pointer.
121 bool is_parsable();
122
123 // Some perm gen objects that have been allocated and initialized
124 // can be changed by the VM when not at a safe point (class rededfinition
125 // is an example). Such objects should not be examined by the
126 // concurrent processing of a garbage collector if is_conc_safe()
127 // returns false.
128 bool is_conc_safe();
129
130 // type test operations (inlined in oop.inline.h)
131 bool is_instance() const;
132 bool is_instanceMirror() const;
133 bool is_instanceRef() const;
134 bool is_array() const;
135 bool is_objArray() const;
136 bool is_klass() const;
137 bool is_thread() const;
138 bool is_method() const;
139 bool is_constMethod() const;
140 bool is_methodData() const;
141 bool is_constantPool() const;
142 bool is_constantPoolCache() const;
143 bool is_typeArray() const;
144 bool is_javaArray() const;
145 bool is_compiledICHolder() const;
146
147 private:
148 // field addresses in oop
149 void* field_base(int offset) const;
150
151 jbyte* byte_field_addr(int offset) const;
152 jchar* char_field_addr(int offset) const;
153 jboolean* bool_field_addr(int offset) const;
154 jint* int_field_addr(int offset) const;
155 jshort* short_field_addr(int offset) const;
156 jlong* long_field_addr(int offset) const;
157 jfloat* float_field_addr(int offset) const;
158 jdouble* double_field_addr(int offset) const;
159 address* address_field_addr(int offset) const;
160
161 public:
162 // Need this as public for garbage collection.
163 template <class T> T* obj_field_addr(int offset) const;
164
165 static bool is_null(oop obj);
166 static bool is_null(narrowOop obj);
167
168 // Decode an oop pointer from a narrowOop if compressed.
169 // These are overloaded for oop and narrowOop as are the other functions
170 // below so that they can be called in template functions.
171 static oop decode_heap_oop_not_null(oop v);
172 static oop decode_heap_oop_not_null(narrowOop v);
173 static oop decode_heap_oop(oop v);
174 static oop decode_heap_oop(narrowOop v);
175
176 // Encode an oop pointer to a narrow oop. The or_null versions accept
177 // null oop pointer, others do not in order to eliminate the
178 // null checking branches.
179 static narrowOop encode_heap_oop_not_null(oop v);
180 static narrowOop encode_heap_oop(oop v);
181
182 // Load an oop out of the Java heap
183 static narrowOop load_heap_oop(narrowOop* p);
184 static oop load_heap_oop(oop* p);
185
186 // Load an oop out of Java heap and decode it to an uncompressed oop.
187 static oop load_decode_heap_oop_not_null(narrowOop* p);
188 static oop load_decode_heap_oop_not_null(oop* p);
189 static oop load_decode_heap_oop(narrowOop* p);
190 static oop load_decode_heap_oop(oop* p);
191
192 // Store an oop into the heap.
193 static void store_heap_oop(narrowOop* p, narrowOop v);
194 static void store_heap_oop(oop* p, oop v);
195
196 // Encode oop if UseCompressedOops and store into the heap.
197 static void encode_store_heap_oop_not_null(narrowOop* p, oop v);
198 static void encode_store_heap_oop_not_null(oop* p, oop v);
199 static void encode_store_heap_oop(narrowOop* p, oop v);
200 static void encode_store_heap_oop(oop* p, oop v);
201
202 static void release_store_heap_oop(volatile narrowOop* p, narrowOop v);
203 static void release_store_heap_oop(volatile oop* p, oop v);
204
205 static void release_encode_store_heap_oop_not_null(volatile narrowOop* p, oop v);
206 static void release_encode_store_heap_oop_not_null(volatile oop* p, oop v);
207 static void release_encode_store_heap_oop(volatile narrowOop* p, oop v);
208 static void release_encode_store_heap_oop(volatile oop* p, oop v);
209
210 static oop atomic_exchange_oop(oop exchange_value, volatile HeapWord *dest);
211 static oop atomic_compare_exchange_oop(oop exchange_value,
212 volatile HeapWord *dest,
213 oop compare_value);
214
215 // Access to fields in a instanceOop through these methods.
216 oop obj_field(int offset) const;
217 void obj_field_put(int offset, oop value);
218 void obj_field_raw_put(int offset, oop value);
219
220 jbyte byte_field(int offset) const;
221 void byte_field_put(int offset, jbyte contents);
222
223 jchar char_field(int offset) const;
224 void char_field_put(int offset, jchar contents);
225
226 jboolean bool_field(int offset) const;
227 void bool_field_put(int offset, jboolean contents);
228
229 jint int_field(int offset) const;
230 void int_field_put(int offset, jint contents);
231
232 jshort short_field(int offset) const;
233 void short_field_put(int offset, jshort contents);
234
235 jlong long_field(int offset) const;
236 void long_field_put(int offset, jlong contents);
237
238 jfloat float_field(int offset) const;
239 void float_field_put(int offset, jfloat contents);
240
241 jdouble double_field(int offset) const;
242 void double_field_put(int offset, jdouble contents);
243
244 address address_field(int offset) const;
245 void address_field_put(int offset, address contents);
246
247 oop obj_field_acquire(int offset) const;
248 void release_obj_field_put(int offset, oop value);
249
250 jbyte byte_field_acquire(int offset) const;
251 void release_byte_field_put(int offset, jbyte contents);
252
253 jchar char_field_acquire(int offset) const;
254 void release_char_field_put(int offset, jchar contents);
255
256 jboolean bool_field_acquire(int offset) const;
257 void release_bool_field_put(int offset, jboolean contents);
258
259 jint int_field_acquire(int offset) const;
260 void release_int_field_put(int offset, jint contents);
261
262 jshort short_field_acquire(int offset) const;
263 void release_short_field_put(int offset, jshort contents);
264
265 jlong long_field_acquire(int offset) const;
266 void release_long_field_put(int offset, jlong contents);
267
268 jfloat float_field_acquire(int offset) const;
269 void release_float_field_put(int offset, jfloat contents);
270
271 jdouble double_field_acquire(int offset) const;
272 void release_double_field_put(int offset, jdouble contents);
273
274 address address_field_acquire(int offset) const;
275 void release_address_field_put(int offset, address contents);
276
277 // printing functions for VM debugging
278 void print_on(outputStream* st) const; // First level print
279 void print_value_on(outputStream* st) const; // Second level print.
280 void print_address_on(outputStream* st) const; // Address printing
281
282 // printing on default output stream
283 void print();
284 void print_value();
285 void print_address();
286
287 // return the print strings
288 char* print_string();
289 char* print_value_string();
290
291 // verification operations
292 void verify_on(outputStream* st);
293 void verify();
294 void verify_old_oop(oop* p, bool allow_dirty);
295 void verify_old_oop(narrowOop* p, bool allow_dirty);
296
297 // tells whether this oop is partially constructed (gc during class loading)
298 bool partially_loaded();
299 void set_partially_loaded();
300
301 // locking operations
302 bool is_locked() const;
303 bool is_unlocked() const;
304 bool has_bias_pattern() const;
305
306 // asserts
307 bool is_oop(bool ignore_mark_word = false) const;
308 bool is_oop_or_null(bool ignore_mark_word = false) const;
309 #ifndef PRODUCT
310 bool is_unlocked_oop() const;
311 #endif
312
313 // garbage collection
314 bool is_gc_marked() const;
315 // Apply "MarkSweep::mark_and_push" to (the address of) every non-NULL
316 // reference field in "this".
317 void follow_contents(void);
318 void follow_header(void);
319
320 #ifndef SERIALGC
321 // Parallel Scavenge
322 void push_contents(PSPromotionManager* pm);
323
324 // Parallel Old
325 void update_contents(ParCompactionManager* cm);
326
327 void follow_contents(ParCompactionManager* cm);
328 void follow_header(ParCompactionManager* cm);
329 #endif // SERIALGC
330
331 bool is_perm() const;
332 bool is_perm_or_null() const;
333 bool is_scavengable() const;
334 bool is_shared() const;
335 bool is_shared_readonly() const;
336 bool is_shared_readwrite() const;
337
338 // Forward pointer operations for scavenge
339 bool is_forwarded() const;
340
341 void forward_to(oop p);
342 bool cas_forward_to(oop p, markOop compare);
343
344 #ifndef SERIALGC
345 // Like "forward_to", but inserts the forwarding pointer atomically.
346 // Exactly one thread succeeds in inserting the forwarding pointer, and
347 // this call returns "NULL" for that thread; any other thread has the
348 // value of the forwarding pointer returned and does not modify "this".
349 oop forward_to_atomic(oop p);
350 #endif // SERIALGC
351
352 oop forwardee() const;
353
354 // Age of object during scavenge
355 int age() const;
356 void incr_age();
357
358 // Adjust all pointers in this object to point at it's forwarded location and
359 // return the size of this oop. This is used by the MarkSweep collector.
360 int adjust_pointers();
361 void adjust_header();
362
363 #ifndef SERIALGC
364 // Parallel old
365 void update_header();
366 #endif // SERIALGC
367
368 // mark-sweep support
369 void follow_body(int begin, int end);
370
371 // Fast access to barrier set
372 static BarrierSet* bs() { return _bs; }
373 static void set_bs(BarrierSet* bs) { _bs = bs; }
374
375 // iterators, returns size of object
376 #define OOP_ITERATE_DECL(OopClosureType, nv_suffix) \
377 int oop_iterate(OopClosureType* blk); \
378 int oop_iterate(OopClosureType* blk, MemRegion mr); // Only in mr.
379
380 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_DECL)
381 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_DECL)
382
383 #ifndef SERIALGC
384
385 #define OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \
386 int oop_iterate_backwards(OopClosureType* blk);
387
388 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_BACKWARDS_DECL)
389 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_BACKWARDS_DECL)
390 #endif
391
392 void oop_iterate_header(OopClosure* blk);
393 void oop_iterate_header(OopClosure* blk, MemRegion mr);
394
395 // identity hash; returns the identity hash key (computes it if necessary)
396 // NOTE with the introduction of UseBiasedLocking that identity_hash() might reach a
397 // safepoint if called on a biased object. Calling code must be aware of that.
398 intptr_t identity_hash();
399 intptr_t slow_identity_hash();
400
401 // marks are forwarded to stack when object is locked
402 bool has_displaced_mark() const;
403 markOop displaced_mark() const;
404 void set_displaced_mark(markOop m);
405
406 // for code generation
407 static int mark_offset_in_bytes() { return offset_of(oopDesc, _mark); }
408 static int klass_offset_in_bytes() { return offset_of(oopDesc, _metadata._klass); }
409 static int klass_gap_offset_in_bytes();
410 };
411
412 #endif // SHARE_VM_OOPS_OOP_HPP