1 /*
2 * Copyright (c) 1997, 2016, 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 "gc/shared/specialized_oop_closures.hpp"
29 #include "memory/iterator.hpp"
30 #include "memory/memRegion.hpp"
31 #include "oops/metadata.hpp"
32 #include "utilities/macros.hpp"
33
34 // oopDesc is the top baseclass for objects classes. The {name}Desc classes describe
35 // the format of Java objects so the fields can be accessed from C++.
36 // oopDesc is abstract.
37 // (see oopHierarchy for complete oop class hierarchy)
38 //
39 // no virtual functions allowed
40
41 // store into oop with store check
42 template <class T> inline void oop_store(T* p, oop v);
43 template <class T> inline void oop_store(volatile T* p, oop v);
44
45 extern bool always_do_update_barrier;
46
47 // Forward declarations.
48 class OopClosure;
49 class ScanClosure;
50 class FastScanClosure;
51 class FilteringClosure;
52 class BarrierSet;
53 class CMSIsAliveClosure;
54
55 class PSPromotionManager;
56 class ParCompactionManager;
57
58 class oopDesc {
59 friend class VMStructs;
60 friend class JVMCIVMStructs;
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 inline void release_set_mark(markOop m);
78 inline 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 inline void init_mark();
83
84 inline Klass* klass() const;
85 inline Klass* klass_or_null() const volatile;
86 inline Klass* klass_or_null_acquire() const volatile;
87 inline Klass** klass_addr();
88 inline narrowKlass* compressed_klass_addr();
89
90 inline void set_klass(Klass* k);
91 inline void release_set_klass(Klass* k);
92
93 // For klass field compression
94 inline int klass_gap() const;
95 inline void set_klass_gap(int z);
96 // For when the klass pointer is being used as a linked list "next" field.
97 inline void set_klass_to_list_ptr(oop k);
98 inline oop list_ptr_from_klass();
99
100 // size of object header, aligned to platform wordSize
101 static int header_size() { return sizeof(oopDesc)/HeapWordSize; }
102
103 // Returns whether this is an instance of k or an instance of a subclass of k
104 inline bool is_a(Klass* k) const;
105
106 // Returns the actual oop size of the object
107 inline int size();
108
109 // Sometimes (for complicated concurrency-related reasons), it is useful
110 // to be able to figure out the size of an object knowing its klass.
111 inline int size_given_klass(Klass* klass);
112
113 // type test operations (inlined in oop.inline.hpp)
114 inline bool is_instance() const;
115 inline bool is_array() const;
116 inline bool is_objArray() const;
117 inline bool is_typeArray() const;
118
119 // type test operations that don't require inclusion of oop.inline.hpp.
120 bool is_instance_noinline() const;
121 bool is_array_noinline() const;
122 bool is_objArray_noinline() const;
123 bool is_typeArray_noinline() const;
124
125 private:
126 // field addresses in oop
127 inline void* field_base(int offset) const;
128
129 inline jbyte* byte_field_addr(int offset) const;
130 inline jchar* char_field_addr(int offset) const;
131 inline jboolean* bool_field_addr(int offset) const;
132 inline jint* int_field_addr(int offset) const;
133 inline jshort* short_field_addr(int offset) const;
134 inline jlong* long_field_addr(int offset) const;
135 inline jfloat* float_field_addr(int offset) const;
136 inline jdouble* double_field_addr(int offset) const;
137 inline Metadata** metadata_field_addr(int offset) const;
138
139 public:
140 // Need this as public for garbage collection.
141 template <class T> inline T* obj_field_addr(int offset) const;
142
143 // Needed for javaClasses
144 inline address* address_field_addr(int offset) const;
145
146 inline static bool is_null(oop obj) { return obj == NULL; }
147 inline static bool is_null(narrowOop obj) { return obj == 0; }
148
149 // Decode an oop pointer from a narrowOop if compressed.
150 // These are overloaded for oop and narrowOop as are the other functions
151 // below so that they can be called in template functions.
152 static inline oop decode_heap_oop_not_null(oop v) { return v; }
153 static inline oop decode_heap_oop_not_null(narrowOop v);
154 static inline oop decode_heap_oop(oop v) { return v; }
155 static inline oop decode_heap_oop(narrowOop v);
156
157 // Encode an oop pointer to a narrow oop. The or_null versions accept
158 // null oop pointer, others do not in order to eliminate the
159 // null checking branches.
160 static inline narrowOop encode_heap_oop_not_null(oop v);
161 static inline narrowOop encode_heap_oop(oop v);
162
163 // Load an oop out of the Java heap as is without decoding.
164 // Called by GC to check for null before decoding.
165 static inline narrowOop load_heap_oop(narrowOop* p) { return *p; }
166 static inline oop load_heap_oop(oop* p) { return *p; }
167
168 // Load an oop out of Java heap and decode it to an uncompressed oop.
169 static inline oop load_decode_heap_oop_not_null(narrowOop* p);
170 static inline oop load_decode_heap_oop_not_null(oop* p) { return *p; }
171 static inline oop load_decode_heap_oop(narrowOop* p);
172 static inline oop load_decode_heap_oop(oop* p) { return *p; }
173
174 // Store already encoded heap oop into the heap.
175 static inline void store_heap_oop(narrowOop* p, narrowOop v) { *p = v; }
176 static inline void store_heap_oop(oop* p, oop v) { *p = v; }
177
178 // Encode oop if UseCompressedOops and store into the heap.
179 static inline void encode_store_heap_oop_not_null(narrowOop* p, oop v);
180 static inline void encode_store_heap_oop_not_null(oop* p, oop v) { *p = v; }
181 static inline void encode_store_heap_oop(narrowOop* p, oop v);
182 static inline void encode_store_heap_oop(oop* p, oop v) { *p = v; }
183
184 static inline void release_store_heap_oop(volatile narrowOop* p, narrowOop v);
185 static inline void release_store_heap_oop(volatile oop* p, oop v);
186
187 static inline void release_encode_store_heap_oop_not_null(volatile narrowOop* p, oop v);
188 static inline void release_encode_store_heap_oop_not_null(volatile oop* p, oop v);
189 static inline void release_encode_store_heap_oop(volatile narrowOop* p, oop v);
190 static inline void release_encode_store_heap_oop(volatile oop* p, oop v);
191
192 static inline oop atomic_exchange_oop(oop exchange_value, volatile HeapWord *dest);
193 static inline oop atomic_compare_exchange_oop(oop exchange_value,
194 volatile HeapWord *dest,
195 oop compare_value,
196 bool prebarrier = false);
197
198 // Access to fields in a instanceOop through these methods.
199 inline oop obj_field(int offset) const;
200 inline void obj_field_put(int offset, oop value);
201 inline void obj_field_put_raw(int offset, oop value);
202 inline void obj_field_put_volatile(int offset, oop value);
203
204 inline Metadata* metadata_field(int offset) const;
205 inline void metadata_field_put(int offset, Metadata* value);
206
207 inline jbyte byte_field(int offset) const;
208 inline void byte_field_put(int offset, jbyte contents);
209
210 inline jchar char_field(int offset) const;
211 inline void char_field_put(int offset, jchar contents);
212
213 inline jboolean bool_field(int offset) const;
214 inline void bool_field_put(int offset, jboolean contents);
215
216 inline jint int_field(int offset) const;
217 inline void int_field_put(int offset, jint contents);
218
219 inline jshort short_field(int offset) const;
220 inline void short_field_put(int offset, jshort contents);
221
222 inline jlong long_field(int offset) const;
223 inline void long_field_put(int offset, jlong contents);
224
225 inline jfloat float_field(int offset) const;
226 inline void float_field_put(int offset, jfloat contents);
227
228 inline jdouble double_field(int offset) const;
229 inline void double_field_put(int offset, jdouble contents);
230
231 inline address address_field(int offset) const;
232 inline void address_field_put(int offset, address contents);
233
234 inline oop obj_field_acquire(int offset) const;
235 inline void release_obj_field_put(int offset, oop value);
236
237 inline jbyte byte_field_acquire(int offset) const;
238 inline void release_byte_field_put(int offset, jbyte contents);
239
240 inline jchar char_field_acquire(int offset) const;
241 inline void release_char_field_put(int offset, jchar contents);
242
243 inline jboolean bool_field_acquire(int offset) const;
244 inline void release_bool_field_put(int offset, jboolean contents);
245
246 inline jint int_field_acquire(int offset) const;
247 inline void release_int_field_put(int offset, jint contents);
248
249 inline jshort short_field_acquire(int offset) const;
250 inline void release_short_field_put(int offset, jshort contents);
251
252 inline jlong long_field_acquire(int offset) const;
253 inline void release_long_field_put(int offset, jlong contents);
254
255 inline jfloat float_field_acquire(int offset) const;
256 inline void release_float_field_put(int offset, jfloat contents);
257
258 inline jdouble double_field_acquire(int offset) const;
259 inline void release_double_field_put(int offset, jdouble contents);
260
261 inline address address_field_acquire(int offset) const;
262 inline void release_address_field_put(int offset, address contents);
263
264 // printing functions for VM debugging
265 void print_on(outputStream* st) const; // First level print
266 void print_value_on(outputStream* st) const; // Second level print.
267 void print_address_on(outputStream* st) const; // Address printing
268
269 // printing on default output stream
270 void print();
271 void print_value();
272 void print_address();
273
274 // return the print strings
275 char* print_string();
276 char* print_value_string();
277
278 // verification operations
279 void verify_on(outputStream* st);
280 void verify();
281
282 // locking operations
283 inline bool is_locked() const;
284 inline bool is_unlocked() const;
285 inline bool has_bias_pattern() const;
286
287 // asserts
288 inline bool is_oop(bool ignore_mark_word = false) const;
289 inline bool is_oop_or_null(bool ignore_mark_word = false) const;
290 #ifndef PRODUCT
291 inline bool is_unlocked_oop() const;
292 #endif
293
294 // garbage collection
295 inline bool is_gc_marked() const;
296
297 inline bool is_scavengable() const;
298
299 // Forward pointer operations for scavenge
300 inline bool is_forwarded() const;
301
302 inline void forward_to(oop p);
303 inline bool cas_forward_to(oop p, markOop compare);
304
305 #if INCLUDE_ALL_GCS
306 // Like "forward_to", but inserts the forwarding pointer atomically.
307 // Exactly one thread succeeds in inserting the forwarding pointer, and
308 // this call returns "NULL" for that thread; any other thread has the
309 // value of the forwarding pointer returned and does not modify "this".
310 inline oop forward_to_atomic(oop p);
311 #endif // INCLUDE_ALL_GCS
312
313 inline oop forwardee() const;
314
315 // Age of object during scavenge
316 inline uint age() const;
317 inline void incr_age();
318
319 // mark-sweep support
320 void follow_body(int begin, int end);
321
322 // Fast access to barrier set
323 static BarrierSet* bs() { return _bs; }
324 static void set_bs(BarrierSet* bs) { _bs = bs; }
325
326 // Garbage Collection support
327
328 // Mark Sweep
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 inline int ms_adjust_pointers();
332 #if INCLUDE_ALL_GCS
333 // Parallel Compact
334 inline void pc_follow_contents(ParCompactionManager* cm);
335 inline void pc_update_contents(ParCompactionManager* cm);
336 // Parallel Scavenge
337 inline void ps_push_contents(PSPromotionManager* pm);
338 #endif
339
340
341 // iterators, returns size of object
342 #define OOP_ITERATE_DECL(OopClosureType, nv_suffix) \
343 inline void oop_iterate(OopClosureType* blk); \
344 inline void oop_iterate(OopClosureType* blk, MemRegion mr); // Only in mr.
345
346 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_DECL)
347 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_DECL)
348
349 #define OOP_ITERATE_SIZE_DECL(OopClosureType, nv_suffix) \
350 inline int oop_iterate_size(OopClosureType* blk); \
351 inline int oop_iterate_size(OopClosureType* blk, MemRegion mr); // Only in mr.
352
353 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_SIZE_DECL)
354 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_SIZE_DECL)
355
356
357 #if INCLUDE_ALL_GCS
358
359 #define OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \
360 inline void oop_iterate_backwards(OopClosureType* blk);
361
362 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_BACKWARDS_DECL)
363 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_BACKWARDS_DECL)
364
365 #endif // INCLUDE_ALL_GCS
366
367 inline int oop_iterate_no_header(OopClosure* bk);
368 inline int oop_iterate_no_header(OopClosure* bk, MemRegion mr);
369
370 // identity hash; returns the identity hash key (computes it if necessary)
371 // NOTE with the introduction of UseBiasedLocking that identity_hash() might reach a
372 // safepoint if called on a biased object. Calling code must be aware of that.
373 inline intptr_t identity_hash();
374 intptr_t slow_identity_hash();
375
376 // Alternate hashing code if string table is rehashed
377 unsigned int new_hash(juint seed);
378
379 // marks are forwarded to stack when object is locked
380 inline bool has_displaced_mark() const;
381 inline markOop displaced_mark() const;
382 inline void set_displaced_mark(markOop m);
383
384 static bool has_klass_gap();
385
386 // for code generation
387 static int mark_offset_in_bytes() { return offset_of(oopDesc, _mark); }
388 static int klass_offset_in_bytes() { return offset_of(oopDesc, _metadata._klass); }
389 static int klass_gap_offset_in_bytes() {
390 assert(has_klass_gap(), "only applicable to compressed klass pointers");
391 return klass_offset_in_bytes() + sizeof(narrowKlass);
392 }
393 };
394
395 #endif // SHARE_VM_OOPS_OOP_HPP