1 /*
2 * Copyright (c) 1997, 2021, 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_OOPS_OOP_INLINE_HPP
26 #define SHARE_OOPS_OOP_INLINE_HPP
27
28 #include "oops/oop.hpp"
29
30 #include "memory/universe.hpp"
31 #include "oops/access.inline.hpp"
32 #include "oops/arrayKlass.hpp"
33 #include "oops/arrayOop.hpp"
34 #include "oops/compressedOops.inline.hpp"
35 #include "oops/markWord.hpp"
36 #include "oops/oopsHierarchy.hpp"
37 #include "runtime/atomic.hpp"
38 #include "runtime/globals.hpp"
39 #include "utilities/align.hpp"
40 #include "utilities/debug.hpp"
41 #include "utilities/macros.hpp"
42 #include "utilities/globalDefinitions.hpp"
43
44 // Implementation of all inlined member functions defined in oop.hpp
45 // We need a separate file to avoid circular references
46
47 markWord oopDesc::mark() const {
48 return Atomic::load(&_mark);
49 }
50
51 markWord oopDesc::mark_acquire() const {
52 return Atomic::load_acquire(&_mark);
53 }
54
55 markWord* oopDesc::mark_addr() const {
56 return (markWord*) &_mark;
57 }
58
59 void oopDesc::set_mark(markWord m) {
60 Atomic::store(&_mark, m);
61 }
62
63 void oopDesc::set_mark(HeapWord* mem, markWord m) {
64 *(markWord*)(((char*)mem) + mark_offset_in_bytes()) = m;
65 }
66
67 void oopDesc::release_set_mark(markWord m) {
68 Atomic::release_store(&_mark, m);
69 }
70
71 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark) {
72 return Atomic::cmpxchg(&_mark, old_mark, new_mark);
73 }
74
75 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark, atomic_memory_order order) {
76 return Atomic::cmpxchg(&_mark, old_mark, new_mark, order);
77 }
78
79 void oopDesc::init_mark() {
80 set_mark(markWord::prototype());
81 }
82
83 Klass* oopDesc::klass() const {
84 if (UseCompressedClassPointers) {
85 return CompressedKlassPointers::decode_not_null(_metadata._compressed_klass);
86 } else {
87 return _metadata._klass;
88 }
89 }
90
91 Klass* oopDesc::klass_or_null() const {
92 if (UseCompressedClassPointers) {
93 return CompressedKlassPointers::decode(_metadata._compressed_klass);
94 } else {
95 return _metadata._klass;
96 }
97 }
98
99 Klass* oopDesc::klass_or_null_acquire() const {
100 if (UseCompressedClassPointers) {
101 narrowKlass nklass = Atomic::load_acquire(&_metadata._compressed_klass);
102 return CompressedKlassPointers::decode(nklass);
103 } else {
104 return Atomic::load_acquire(&_metadata._klass);
105 }
106 }
107
108 void oopDesc::set_klass(Klass* k) {
109 assert(Universe::is_bootstrapping() || (k != NULL && k->is_klass()), "incorrect Klass");
110 if (UseCompressedClassPointers) {
111 _metadata._compressed_klass = CompressedKlassPointers::encode_not_null(k);
112 } else {
113 _metadata._klass = k;
114 }
115 }
116
117 void oopDesc::release_set_klass(HeapWord* mem, Klass* k) {
118 assert(Universe::is_bootstrapping() || (k != NULL && k->is_klass()), "incorrect Klass");
119 char* raw_mem = ((char*)mem + klass_offset_in_bytes());
120 if (UseCompressedClassPointers) {
121 Atomic::release_store((narrowKlass*)raw_mem,
122 CompressedKlassPointers::encode_not_null(k));
123 } else {
124 Atomic::release_store((Klass**)raw_mem, k);
125 }
126 }
127
128 int oopDesc::klass_gap() const {
129 return *(int*)(((intptr_t)this) + klass_gap_offset_in_bytes());
130 }
131
132 void oopDesc::set_klass_gap(HeapWord* mem, int v) {
133 if (UseCompressedClassPointers) {
134 *(int*)(((char*)mem) + klass_gap_offset_in_bytes()) = v;
135 }
136 }
137
138 void oopDesc::set_klass_gap(int v) {
139 set_klass_gap((HeapWord*)this, v);
140 }
141
142 bool oopDesc::is_a(Klass* k) const {
143 return klass()->is_subtype_of(k);
144 }
145
146 int oopDesc::size() {
147 return size_given_klass(klass());
148 }
149
150 int oopDesc::size_given_klass(Klass* klass) {
151 int lh = klass->layout_helper();
152 int s;
153
154 // lh is now a value computed at class initialization that may hint
155 // at the size. For instances, this is positive and equal to the
156 // size. For arrays, this is negative and provides log2 of the
157 // array element size. For other oops, it is zero and thus requires
158 // a virtual call.
159 //
160 // We go to all this trouble because the size computation is at the
161 // heart of phase 2 of mark-compaction, and called for every object,
162 // alive or dead. So the speed here is equal in importance to the
163 // speed of allocation.
164
165 if (lh > Klass::_lh_neutral_value) {
166 if (!Klass::layout_helper_needs_slow_path(lh)) {
167 s = lh >> LogHeapWordSize; // deliver size scaled by wordSize
168 } else {
169 s = klass->oop_size(this);
170 }
171 } else if (lh <= Klass::_lh_neutral_value) {
172 // The most common case is instances; fall through if so.
173 if (lh < Klass::_lh_neutral_value) {
174 // Second most common case is arrays. We have to fetch the
175 // length of the array, shift (multiply) it appropriately,
176 // up to wordSize, add the header, and align to object size.
177 size_t size_in_bytes;
178 size_t array_length = (size_t) ((arrayOop)this)->length();
179 size_in_bytes = array_length << Klass::layout_helper_log2_element_size(lh);
180 size_in_bytes += Klass::layout_helper_header_size(lh);
181
182 // This code could be simplified, but by keeping array_header_in_bytes
183 // in units of bytes and doing it this way we can round up just once,
184 // skipping the intermediate round to HeapWordSize.
185 s = (int)(align_up(size_in_bytes, MinObjAlignmentInBytes) / HeapWordSize);
186
187 // UseParallelGC and UseG1GC can change the length field
188 // of an "old copy" of an object array in the young gen so it indicates
189 // the grey portion of an already copied array. This will cause the first
190 // disjunct below to fail if the two comparands are computed across such
191 // a concurrent change.
192 assert((s == klass->oop_size(this)) ||
193 (Universe::is_gc_active() && is_objArray() && is_forwarded() && (get_UseParallelGC() || get_UseG1GC())),
194 "wrong array object size");
195 } else {
196 // Must be zero, so bite the bullet and take the virtual call.
197 s = klass->oop_size(this);
198 }
199 }
200
201 assert(s > 0, "Oop size must be greater than zero, not %d", s);
202 assert(is_object_aligned(s), "Oop size is not properly aligned: %d", s);
203 return s;
204 }
205
206 bool oopDesc::is_instance() const { return klass()->is_instance_klass(); }
207 bool oopDesc::is_array() const { return klass()->is_array_klass(); }
208 bool oopDesc::is_objArray() const { return klass()->is_objArray_klass(); }
209 bool oopDesc::is_typeArray() const { return klass()->is_typeArray_klass(); }
210
211 void* oopDesc::field_addr(int offset) const { return reinterpret_cast<void*>(cast_from_oop<intptr_t>(as_oop()) + offset); }
212
213 template <class T>
214 T* oopDesc::obj_field_addr(int offset) const { return (T*) field_addr(offset); }
215
216 template <typename T>
217 size_t oopDesc::field_offset(T* p) const { return pointer_delta((void*)p, (void*)this, 1); }
218
219 template <DecoratorSet decorators>
220 inline oop oopDesc::obj_field_access(int offset) const { return HeapAccess<decorators>::oop_load_at(as_oop(), offset); }
221 inline oop oopDesc::obj_field(int offset) const { return HeapAccess<>::oop_load_at(as_oop(), offset); }
222
223 inline void oopDesc::obj_field_put(int offset, oop value) { HeapAccess<>::oop_store_at(as_oop(), offset, value); }
224
225 inline jbyte oopDesc::byte_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
226 inline void oopDesc::byte_field_put(int offset, jbyte value) { HeapAccess<>::store_at(as_oop(), offset, value); }
227
228 inline jchar oopDesc::char_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
229 inline void oopDesc::char_field_put(int offset, jchar value) { HeapAccess<>::store_at(as_oop(), offset, value); }
230
231 inline jboolean oopDesc::bool_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
232 inline void oopDesc::bool_field_put(int offset, jboolean value) { HeapAccess<>::store_at(as_oop(), offset, jboolean(value & 1)); }
233 inline jboolean oopDesc::bool_field_volatile(int offset) const { return HeapAccess<MO_SEQ_CST>::load_at(as_oop(), offset); }
234 inline void oopDesc::bool_field_put_volatile(int offset, jboolean value) { HeapAccess<MO_SEQ_CST>::store_at(as_oop(), offset, jboolean(value & 1)); }
235 inline jshort oopDesc::short_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
236 inline void oopDesc::short_field_put(int offset, jshort value) { HeapAccess<>::store_at(as_oop(), offset, value); }
237
238 inline jint oopDesc::int_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
239 inline void oopDesc::int_field_put(int offset, jint value) { HeapAccess<>::store_at(as_oop(), offset, value); }
240
241 inline jlong oopDesc::long_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
242 inline void oopDesc::long_field_put(int offset, jlong value) { HeapAccess<>::store_at(as_oop(), offset, value); }
243
244 inline jfloat oopDesc::float_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
245 inline void oopDesc::float_field_put(int offset, jfloat value) { HeapAccess<>::store_at(as_oop(), offset, value); }
246
247 inline jdouble oopDesc::double_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
248 inline void oopDesc::double_field_put(int offset, jdouble value) { HeapAccess<>::store_at(as_oop(), offset, value); }
249
250 bool oopDesc::is_locked() const {
251 return mark().is_locked();
252 }
253
254 bool oopDesc::is_unlocked() const {
255 return mark().is_unlocked();
256 }
257
258 // Used only for markSweep, scavenging
259 bool oopDesc::is_gc_marked() const {
260 return mark().is_marked();
261 }
262
263 // Used by scavengers
264 bool oopDesc::is_forwarded() const {
265 // The extra heap check is needed since the obj might be locked, in which case the
266 // mark would point to a stack location and have the sentinel bit cleared
267 return mark().is_marked();
268 }
269
270 // Used by scavengers
271 void oopDesc::forward_to(oop p) {
272 verify_forwardee(p);
273 markWord m = markWord::encode_pointer_as_mark(p);
274 assert(m.decode_pointer() == p, "encoding must be reversable");
275 set_mark(m);
276 }
277
278 oop oopDesc::forward_to_atomic(oop p, markWord compare, atomic_memory_order order) {
279 verify_forwardee(p);
280 markWord m = markWord::encode_pointer_as_mark(p);
281 assert(m.decode_pointer() == p, "encoding must be reversable");
282 markWord old_mark = cas_set_mark(m, compare, order);
283 if (old_mark == compare) {
284 return NULL;
285 } else {
286 return cast_to_oop(old_mark.decode_pointer());
287 }
288 }
289
290 // Note that the forwardee is not the same thing as the displaced_mark.
291 // The forwardee is used when copying during scavenge and mark-sweep.
292 // It does need to clear the low two locking- and GC-related bits.
293 oop oopDesc::forwardee() const {
294 return cast_to_oop(mark().decode_pointer());
295 }
296
297 // The following method needs to be MT safe.
298 uint oopDesc::age() const {
299 assert(!is_forwarded(), "Attempt to read age from forwarded mark");
300 if (has_displaced_mark()) {
301 return displaced_mark().age();
302 } else {
303 return mark().age();
304 }
305 }
306
307 void oopDesc::incr_age() {
308 assert(!is_forwarded(), "Attempt to increment age of forwarded mark");
309 if (has_displaced_mark()) {
310 set_displaced_mark(displaced_mark().incr_age());
311 } else {
312 set_mark(mark().incr_age());
313 }
314 }
315
316 template <typename OopClosureType>
317 void oopDesc::oop_iterate(OopClosureType* cl) {
318 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass());
319 }
320
321 template <typename OopClosureType>
322 void oopDesc::oop_iterate(OopClosureType* cl, MemRegion mr) {
323 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass(), mr);
324 }
325
326 template <typename OopClosureType>
327 int oopDesc::oop_iterate_size(OopClosureType* cl) {
328 Klass* k = klass();
329 int size = size_given_klass(k);
330 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k);
331 return size;
332 }
333
334 template <typename OopClosureType>
335 int oopDesc::oop_iterate_size(OopClosureType* cl, MemRegion mr) {
336 Klass* k = klass();
337 int size = size_given_klass(k);
338 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k, mr);
339 return size;
340 }
341
342 template <typename OopClosureType>
343 void oopDesc::oop_iterate_backwards(OopClosureType* cl) {
344 oop_iterate_backwards(cl, klass());
345 }
346
347 template <typename OopClosureType>
348 void oopDesc::oop_iterate_backwards(OopClosureType* cl, Klass* k) {
349 assert(k == klass(), "wrong klass");
350 OopIteratorClosureDispatch::oop_oop_iterate_backwards(cl, this, k);
351 }
352
353 bool oopDesc::is_instanceof_or_null(oop obj, Klass* klass) {
354 return obj == NULL || obj->klass()->is_subtype_of(klass);
355 }
356
357 intptr_t oopDesc::identity_hash() {
358 // Fast case; if the object is unlocked and the hash value is set, no locking is needed
359 // Note: The mark must be read into local variable to avoid concurrent updates.
360 markWord mrk = mark();
361 if (mrk.is_unlocked() && !mrk.has_no_hash()) {
362 return mrk.hash();
363 } else if (mrk.is_marked()) {
364 return mrk.hash();
365 } else {
366 return slow_identity_hash();
367 }
368 }
369
370 bool oopDesc::has_displaced_mark() const {
371 return mark().has_displaced_mark_helper();
372 }
373
374 markWord oopDesc::displaced_mark() const {
375 return mark().displaced_mark_helper();
376 }
377
378 void oopDesc::set_displaced_mark(markWord m) {
379 mark().set_displaced_mark_helper(m);
380 }
381
382 bool oopDesc::mark_must_be_preserved() const {
383 return mark_must_be_preserved(mark());
384 }
385
386 bool oopDesc::mark_must_be_preserved(markWord m) const {
387 return m.must_be_preserved(this);
388 }
389
390 #endif // SHARE_OOPS_OOP_INLINE_HPP