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.
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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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 extern bool always_do_update_barrier;
42
43 // Forward declarations.
44 class OopClosure;
45 class ScanClosure;
46 class FastScanClosure;
47 class FilteringClosure;
48 class BarrierSet;
49 class CMSIsAliveClosure;
50
51 class PSPromotionManager;
52 class ParCompactionManager;
53
54 class oopDesc {
55 friend class VMStructs;
56 friend class JVMCIVMStructs;
57 private:
58 volatile markOop _mark;
59 union _metadata {
60 Klass* _klass;
61 narrowKlass _compressed_klass;
62 } _metadata;
63
64 public:
65 markOop mark() const { return _mark; }
66 markOop* mark_addr() const { return (markOop*) &_mark; }
67
68 void set_mark(volatile markOop m) { _mark = m; }
69
70 inline void release_set_mark(markOop m);
71 inline markOop cas_set_mark(markOop new_mark, markOop old_mark);
72
73 // Used only to re-initialize the mark word (e.g., of promoted
74 // objects during a GC) -- requires a valid klass pointer
75 inline void init_mark();
76
77 inline Klass* klass() const;
78 inline Klass* klass_or_null() const volatile;
79 inline Klass* klass_or_null_acquire() const volatile;
80 inline Klass** klass_addr();
81 inline narrowKlass* compressed_klass_addr();
82
83 inline void set_klass(Klass* k);
84 inline void release_set_klass(Klass* k);
85
86 // For klass field compression
87 inline int klass_gap() const;
88 inline void set_klass_gap(int z);
89 // For when the klass pointer is being used as a linked list "next" field.
90 inline void set_klass_to_list_ptr(oop k);
91 inline oop list_ptr_from_klass();
92
93 // size of object header, aligned to platform wordSize
94 static int header_size() { return sizeof(oopDesc)/HeapWordSize; }
95
96 // Returns whether this is an instance of k or an instance of a subclass of k
97 inline bool is_a(Klass* k) const;
98
99 // Returns the actual oop size of the object
100 inline int size();
101
102 // Sometimes (for complicated concurrency-related reasons), it is useful
103 // to be able to figure out the size of an object knowing its klass.
104 inline int size_given_klass(Klass* klass);
105
106 // type test operations (inlined in oop.inline.hpp)
107 inline bool is_instance() const;
108 inline bool is_array() const;
109 inline bool is_objArray() const;
110 inline bool is_typeArray() const;
111
112 // type test operations that don't require inclusion of oop.inline.hpp.
113 bool is_instance_noinline() const;
114 bool is_array_noinline() const;
115 bool is_objArray_noinline() const;
116 bool is_typeArray_noinline() const;
117
118 protected:
119 inline oop as_oop() const { return const_cast<oopDesc*>(this); }
120
121 private:
122 // field addresses in oop
123 inline void* field_base(int offset) const;
124
125 inline jbyte* byte_field_addr(int offset) const;
126 inline jchar* char_field_addr(int offset) const;
127 inline jboolean* bool_field_addr(int offset) const;
128 inline jint* int_field_addr(int offset) const;
129 inline jshort* short_field_addr(int offset) const;
130 inline jlong* long_field_addr(int offset) const;
131 inline jfloat* float_field_addr(int offset) const;
132 inline jdouble* double_field_addr(int offset) const;
133 inline Metadata** metadata_field_addr(int offset) const;
134
135 public:
136 // Need this as public for garbage collection.
137 template <class T> inline T* obj_field_addr(int offset) const;
138
139 // Needed for javaClasses
140 inline address* address_field_addr(int offset) const;
141
142 inline static bool is_null(oop obj) { return obj == NULL; }
143 inline static bool is_null(narrowOop obj) { return obj == 0; }
144
145 // Decode an oop pointer from a narrowOop if compressed.
146 // These are overloaded for oop and narrowOop as are the other functions
147 // below so that they can be called in template functions.
148 static inline oop decode_heap_oop_not_null(oop v) { return v; }
149 static inline oop decode_heap_oop_not_null(narrowOop v);
150 static inline oop decode_heap_oop(oop v) { return v; }
151 static inline oop decode_heap_oop(narrowOop v);
152
153 // Encode an oop pointer to a narrow oop. The or_null versions accept
154 // null oop pointer, others do not in order to eliminate the
155 // null checking branches.
156 static inline narrowOop encode_heap_oop_not_null(oop v);
157 static inline narrowOop encode_heap_oop(oop v);
158
159 // Load an oop out of the Java heap as is without decoding.
160 // Called by GC to check for null before decoding.
161 static inline narrowOop load_heap_oop(narrowOop* p);
162 static inline oop load_heap_oop(oop* p);
163
164 // Load an oop out of Java heap and decode it to an uncompressed oop.
165 static inline oop load_decode_heap_oop_not_null(narrowOop* p);
166 static inline oop load_decode_heap_oop_not_null(oop* p);
167 static inline oop load_decode_heap_oop(narrowOop* p);
168 static inline oop load_decode_heap_oop(oop* p);
169
170 // Store already encoded heap oop into the heap.
171 static inline void store_heap_oop(narrowOop* p, narrowOop v);
172 static inline void store_heap_oop(oop* p, oop v);
173
174 // Encode oop if UseCompressedOops and store into the heap.
175 static inline void encode_store_heap_oop_not_null(narrowOop* p, oop v);
176 static inline void encode_store_heap_oop_not_null(oop* p, oop v);
177 static inline void encode_store_heap_oop(narrowOop* p, oop v);
178 static inline void encode_store_heap_oop(oop* p, oop v);
179
180 // Access to fields in a instanceOop through these methods.
181 oop obj_field(int offset) const;
182 void obj_field_put(int offset, oop value);
183 void obj_field_put_raw(int offset, oop value);
184 void obj_field_put_volatile(int offset, oop value);
185
186 Metadata* metadata_field(int offset) const;
187 void metadata_field_put(int offset, Metadata* value);
188
189 Metadata* metadata_field_acquire(int offset) const;
190 void release_metadata_field_put(int offset, Metadata* value);
191
192 jbyte byte_field(int offset) const;
193 void byte_field_put(int offset, jbyte contents);
194
195 jchar char_field(int offset) const;
196 void char_field_put(int offset, jchar contents);
197
198 jboolean bool_field(int offset) const;
199 void bool_field_put(int offset, jboolean contents);
200
201 jint int_field(int offset) const;
202 void int_field_put(int offset, jint contents);
203
204 jshort short_field(int offset) const;
205 void short_field_put(int offset, jshort contents);
206
207 jlong long_field(int offset) const;
208 void long_field_put(int offset, jlong contents);
209
210 jfloat float_field(int offset) const;
211 void float_field_put(int offset, jfloat contents);
212
213 jdouble double_field(int offset) const;
214 void double_field_put(int offset, jdouble contents);
215
216 address address_field(int offset) const;
217 void address_field_put(int offset, address contents);
218
219 oop obj_field_acquire(int offset) const;
220 void release_obj_field_put(int offset, oop value);
221
222 jbyte byte_field_acquire(int offset) const;
223 void release_byte_field_put(int offset, jbyte contents);
224
225 jchar char_field_acquire(int offset) const;
226 void release_char_field_put(int offset, jchar contents);
227
228 jboolean bool_field_acquire(int offset) const;
229 void release_bool_field_put(int offset, jboolean contents);
230
231 jint int_field_acquire(int offset) const;
232 void release_int_field_put(int offset, jint contents);
233
234 jshort short_field_acquire(int offset) const;
235 void release_short_field_put(int offset, jshort contents);
236
237 jlong long_field_acquire(int offset) const;
238 void release_long_field_put(int offset, jlong contents);
239
240 jfloat float_field_acquire(int offset) const;
241 void release_float_field_put(int offset, jfloat contents);
242
243 jdouble double_field_acquire(int offset) const;
244 void release_double_field_put(int offset, jdouble contents);
245
246 address address_field_acquire(int offset) const;
247 void release_address_field_put(int offset, address contents);
248
249 // printing functions for VM debugging
250 void print_on(outputStream* st) const; // First level print
251 void print_value_on(outputStream* st) const; // Second level print.
252 void print_address_on(outputStream* st) const; // Address printing
253
254 // printing on default output stream
255 void print();
256 void print_value();
257 void print_address();
258
259 // return the print strings
260 char* print_string();
261 char* print_value_string();
262
263 // verification operations
264 void verify_on(outputStream* st);
265 void verify();
266
267 // locking operations
268 inline bool is_locked() const;
269 inline bool is_unlocked() const;
270 inline bool has_bias_pattern() const;
271
272 // asserts and guarantees
273 static bool is_oop(oop obj, bool ignore_mark_word = false);
274 static bool is_oop_or_null(oop obj, bool ignore_mark_word = false);
275 #ifndef PRODUCT
276 inline bool is_unlocked_oop() const;
277 #endif
278
279 // garbage collection
280 inline bool is_gc_marked() const;
281
282 inline bool is_scavengable() const;
283
284 // Forward pointer operations for scavenge
285 inline bool is_forwarded() const;
286
287 inline void forward_to(oop p);
288 inline bool cas_forward_to(oop p, markOop compare);
289
290 #if INCLUDE_ALL_GCS
291 // Like "forward_to", but inserts the forwarding pointer atomically.
292 // Exactly one thread succeeds in inserting the forwarding pointer, and
293 // this call returns "NULL" for that thread; any other thread has the
294 // value of the forwarding pointer returned and does not modify "this".
295 inline oop forward_to_atomic(oop p);
296 #endif // INCLUDE_ALL_GCS
297
298 inline oop forwardee() const;
299
300 // Age of object during scavenge
301 inline uint age() const;
302 inline void incr_age();
303
304 // mark-sweep support
305 void follow_body(int begin, int end);
306
307 // Garbage Collection support
308
309 #if INCLUDE_ALL_GCS
310 // Parallel Compact
311 inline void pc_follow_contents(ParCompactionManager* cm);
312 inline void pc_update_contents(ParCompactionManager* cm);
313 // Parallel Scavenge
314 inline void ps_push_contents(PSPromotionManager* pm);
315 #endif
316
317
318 // iterators, returns size of object
319 #define OOP_ITERATE_DECL(OopClosureType, nv_suffix) \
320 inline void oop_iterate(OopClosureType* blk); \
321 inline void oop_iterate(OopClosureType* blk, MemRegion mr); // Only in mr.
322
323 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_DECL)
324 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_DECL)
325
326 #define OOP_ITERATE_SIZE_DECL(OopClosureType, nv_suffix) \
327 inline int oop_iterate_size(OopClosureType* blk); \
328 inline int oop_iterate_size(OopClosureType* blk, MemRegion mr); // Only in mr.
329
330 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_SIZE_DECL)
331 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_SIZE_DECL)
332
333
334 #if INCLUDE_ALL_GCS
335
336 #define OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \
337 inline void oop_iterate_backwards(OopClosureType* blk);
338
339 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_BACKWARDS_DECL)
340 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_BACKWARDS_DECL)
341
342 #endif // INCLUDE_ALL_GCS
343
344 inline int oop_iterate_no_header(OopClosure* bk);
345 inline int oop_iterate_no_header(OopClosure* bk, MemRegion mr);
346
347 // identity hash; returns the identity hash key (computes it if necessary)
348 // NOTE with the introduction of UseBiasedLocking that identity_hash() might reach a
349 // safepoint if called on a biased object. Calling code must be aware of that.
350 inline intptr_t identity_hash();
351 intptr_t slow_identity_hash();
352
353 // Alternate hashing code if string table is rehashed
354 unsigned int new_hash(juint seed);
355
356 // marks are forwarded to stack when object is locked
357 inline bool has_displaced_mark() const;
358 inline markOop displaced_mark() const;
359 inline void set_displaced_mark(markOop m);
360
361 static bool has_klass_gap();
362
363 // for code generation
364 static int mark_offset_in_bytes() { return offset_of(oopDesc, _mark); }
365 static int klass_offset_in_bytes() { return offset_of(oopDesc, _metadata._klass); }
366 static int klass_gap_offset_in_bytes() {
367 assert(has_klass_gap(), "only applicable to compressed klass pointers");
368 return klass_offset_in_bytes() + sizeof(narrowKlass);
369 }
370
371 static bool is_archive_object(oop p) NOT_CDS_JAVA_HEAP_RETURN_(false);
372 };
373
374 #endif // SHARE_VM_OOPS_OOP_HPP