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