1/*
2 * Copyright (c) 1997, 2017, 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
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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
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
42template <class T> inline void oop_store(T* p, oop v);
43template <class T> inline void oop_store(volatile T* p, oop v);
44
45extern bool always_do_update_barrier;
46
47// Forward declarations.
48class OopClosure;
49class ScanClosure;
50class FastScanClosure;
51class FilteringClosure;
52class BarrierSet;
53class CMSIsAliveClosure;
54
55class PSPromotionManager;
56class ParCompactionManager;
57
58class 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 Metadata* metadata_field_acquire(int offset) const;
208  inline void release_metadata_field_put(int offset, Metadata* value);
209
210  inline jbyte byte_field(int offset) const;
211  inline void byte_field_put(int offset, jbyte contents);
212
213  inline jchar char_field(int offset) const;
214  inline void char_field_put(int offset, jchar contents);
215
216  inline jboolean bool_field(int offset) const;
217  inline void bool_field_put(int offset, jboolean contents);
218
219  inline jint int_field(int offset) const;
220  inline void int_field_put(int offset, jint contents);
221
222  inline jshort short_field(int offset) const;
223  inline void short_field_put(int offset, jshort contents);
224
225  inline jlong long_field(int offset) const;
226  inline void long_field_put(int offset, jlong contents);
227
228  inline jfloat float_field(int offset) const;
229  inline void float_field_put(int offset, jfloat contents);
230
231  inline jdouble double_field(int offset) const;
232  inline void double_field_put(int offset, jdouble contents);
233
234  inline address address_field(int offset) const;
235  inline void address_field_put(int offset, address contents);
236
237  inline oop obj_field_acquire(int offset) const;
238  inline void release_obj_field_put(int offset, oop value);
239
240  inline jbyte byte_field_acquire(int offset) const;
241  inline void release_byte_field_put(int offset, jbyte contents);
242
243  inline jchar char_field_acquire(int offset) const;
244  inline void release_char_field_put(int offset, jchar contents);
245
246  inline jboolean bool_field_acquire(int offset) const;
247  inline void release_bool_field_put(int offset, jboolean contents);
248
249  inline jint int_field_acquire(int offset) const;
250  inline void release_int_field_put(int offset, jint contents);
251
252  inline jshort short_field_acquire(int offset) const;
253  inline void release_short_field_put(int offset, jshort contents);
254
255  inline jlong long_field_acquire(int offset) const;
256  inline void release_long_field_put(int offset, jlong contents);
257
258  inline jfloat float_field_acquire(int offset) const;
259  inline void release_float_field_put(int offset, jfloat contents);
260
261  inline jdouble double_field_acquire(int offset) const;
262  inline void release_double_field_put(int offset, jdouble contents);
263
264  inline address address_field_acquire(int offset) const;
265  inline void release_address_field_put(int offset, address contents);
266
267  // printing functions for VM debugging
268  void print_on(outputStream* st) const;         // First level print
269  void print_value_on(outputStream* st) const;   // Second level print.
270  void print_address_on(outputStream* st) const; // Address printing
271
272  // printing on default output stream
273  void print();
274  void print_value();
275  void print_address();
276
277  // return the print strings
278  char* print_string();
279  char* print_value_string();
280
281  // verification operations
282  void verify_on(outputStream* st);
283  void verify();
284
285  // locking operations
286  inline bool is_locked()   const;
287  inline bool is_unlocked() const;
288  inline bool has_bias_pattern() const;
289
290  // asserts and guarantees
291  static bool is_oop(oop obj, bool ignore_mark_word = false);
292  static bool is_oop_or_null(oop obj, bool ignore_mark_word = false);
293#ifndef PRODUCT
294  inline bool is_unlocked_oop() const;
295#endif
296
297  // garbage collection
298  inline bool is_gc_marked() const;
299
300  inline bool is_scavengable() const;
301
302  // Forward pointer operations for scavenge
303  inline bool is_forwarded() const;
304
305  inline void forward_to(oop p);
306  inline bool cas_forward_to(oop p, markOop compare);
307
308#if INCLUDE_ALL_GCS
309  // Like "forward_to", but inserts the forwarding pointer atomically.
310  // Exactly one thread succeeds in inserting the forwarding pointer, and
311  // this call returns "NULL" for that thread; any other thread has the
312  // value of the forwarding pointer returned and does not modify "this".
313  inline oop forward_to_atomic(oop p);
314#endif // INCLUDE_ALL_GCS
315
316  inline oop forwardee() const;
317
318  // Age of object during scavenge
319  inline uint age() const;
320  inline void incr_age();
321
322  // mark-sweep support
323  void follow_body(int begin, int end);
324
325  // Fast access to barrier set
326  static BarrierSet* bs()            { return _bs; }
327  static void set_bs(BarrierSet* bs) { _bs = bs; }
328
329  // Garbage Collection support
330
331#if INCLUDE_ALL_GCS
332  // Parallel Compact
333  inline void pc_follow_contents(ParCompactionManager* cm);
334  inline void pc_update_contents(ParCompactionManager* cm);
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  static bool is_archive_object(oop p) NOT_CDS_JAVA_HEAP_RETURN_(false);
394};
395
396#endif // SHARE_VM_OOPS_OOP_HPP
397