1 /*
2 * Copyright (c) 1997, 2023, 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_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 "memory/iterator.inline.hpp"
32 #include "oops/access.inline.hpp"
33 #include "oops/arrayKlass.hpp"
34 #include "oops/arrayOop.hpp"
35 #include "oops/compressedOops.inline.hpp"
36 #include "oops/instanceKlass.hpp"
37 #include "oops/markWord.hpp"
38 #include "oops/oopsHierarchy.hpp"
39 #include "runtime/atomic.hpp"
40 #include "runtime/globals.hpp"
41 #include "utilities/align.hpp"
42 #include "utilities/debug.hpp"
43 #include "utilities/macros.hpp"
44 #include "utilities/globalDefinitions.hpp"
45
46 // Implementation of all inlined member functions defined in oop.hpp
47 // We need a separate file to avoid circular references
48
49 markWord oopDesc::mark() const {
50 return Atomic::load(&_mark);
51 }
52
53 markWord oopDesc::mark_acquire() const {
54 return Atomic::load_acquire(&_mark);
55 }
56
57 markWord* oopDesc::mark_addr() const {
58 return (markWord*) &_mark;
59 }
60
61 void oopDesc::set_mark(markWord m) {
62 Atomic::store(&_mark, m);
63 }
64
65 void oopDesc::set_mark(HeapWord* mem, markWord m) {
66 *(markWord*)(((char*)mem) + mark_offset_in_bytes()) = m;
67 }
68
69 void oopDesc::release_set_mark(markWord m) {
70 Atomic::release_store(&_mark, m);
71 }
72
73 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark) {
74 return Atomic::cmpxchg(&_mark, old_mark, new_mark);
75 }
76
77 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark, atomic_memory_order order) {
78 return Atomic::cmpxchg(&_mark, old_mark, new_mark, order);
79 }
80
81 void oopDesc::init_mark() {
82 set_mark(markWord::prototype());
83 }
84
85 Klass* oopDesc::klass() const {
86 if (UseCompressedClassPointers) {
87 return CompressedKlassPointers::decode_not_null(_metadata._compressed_klass);
88 } else {
89 return _metadata._klass;
90 }
91 }
92
93 Klass* oopDesc::klass_or_null() const {
94 if (UseCompressedClassPointers) {
95 return CompressedKlassPointers::decode(_metadata._compressed_klass);
96 } else {
97 return _metadata._klass;
98 }
99 }
100
101 Klass* oopDesc::klass_or_null_acquire() const {
102 if (UseCompressedClassPointers) {
103 narrowKlass nklass = Atomic::load_acquire(&_metadata._compressed_klass);
104 return CompressedKlassPointers::decode(nklass);
105 } else {
106 return Atomic::load_acquire(&_metadata._klass);
107 }
108 }
109
110 void oopDesc::set_klass(Klass* k) {
111 assert(Universe::is_bootstrapping() || (k != NULL && k->is_klass()), "incorrect Klass");
112 if (UseCompressedClassPointers) {
113 _metadata._compressed_klass = CompressedKlassPointers::encode_not_null(k);
114 } else {
115 _metadata._klass = k;
116 }
117 }
118
119 void oopDesc::release_set_klass(HeapWord* mem, Klass* k) {
120 assert(Universe::is_bootstrapping() || (k != NULL && k->is_klass()), "incorrect Klass");
121 char* raw_mem = ((char*)mem + klass_offset_in_bytes());
122 if (UseCompressedClassPointers) {
123 Atomic::release_store((narrowKlass*)raw_mem,
124 CompressedKlassPointers::encode_not_null(k));
125 } else {
126 Atomic::release_store((Klass**)raw_mem, k);
127 }
128 }
129
130 void oopDesc::set_klass_gap(HeapWord* mem, int v) {
131 if (UseCompressedClassPointers) {
132 *(int*)(((char*)mem) + klass_gap_offset_in_bytes()) = v;
133 }
134 }
135
136 bool oopDesc::is_a(Klass* k) const {
137 return klass()->is_subtype_of(k);
138 }
139
140 size_t oopDesc::size() {
141 return size_given_klass(klass());
142 }
143
144 size_t oopDesc::size_given_klass(Klass* klass) {
145 int lh = klass->layout_helper();
146 size_t s;
147
148 // lh is now a value computed at class initialization that may hint
149 // at the size. For instances, this is positive and equal to the
150 // size. For arrays, this is negative and provides log2 of the
151 // array element size. For other oops, it is zero and thus requires
152 // a virtual call.
153 //
154 // We go to all this trouble because the size computation is at the
155 // heart of phase 2 of mark-compaction, and called for every object,
156 // alive or dead. So the speed here is equal in importance to the
157 // speed of allocation.
158
159 if (lh > Klass::_lh_neutral_value) {
160 if (!Klass::layout_helper_needs_slow_path(lh)) {
161 s = lh >> LogHeapWordSize; // deliver size scaled by wordSize
162 } else {
163 s = klass->oop_size(this);
164 }
165 } else if (lh <= Klass::_lh_neutral_value) {
166 // The most common case is instances; fall through if so.
167 if (lh < Klass::_lh_neutral_value) {
168 // Second most common case is arrays. We have to fetch the
169 // length of the array, shift (multiply) it appropriately,
170 // up to wordSize, add the header, and align to object size.
171 size_t size_in_bytes;
172 size_t array_length = (size_t) ((arrayOop)this)->length();
173 size_in_bytes = array_length << Klass::layout_helper_log2_element_size(lh);
174 size_in_bytes += Klass::layout_helper_header_size(lh);
175
176 // This code could be simplified, but by keeping array_header_in_bytes
177 // in units of bytes and doing it this way we can round up just once,
178 // skipping the intermediate round to HeapWordSize.
179 s = align_up(size_in_bytes, MinObjAlignmentInBytes) / HeapWordSize;
180
181 assert(s == klass->oop_size(this) || size_might_change(), "wrong array object size");
182 } else {
183 // Must be zero, so bite the bullet and take the virtual call.
184 s = klass->oop_size(this);
185 }
186 }
187
188 assert(s > 0, "Oop size must be greater than zero, not " SIZE_FORMAT, s);
189 assert(is_object_aligned(s), "Oop size is not properly aligned: " SIZE_FORMAT, s);
190 return s;
191 }
192
193 bool oopDesc::is_instance() const { return klass()->is_instance_klass(); }
194 bool oopDesc::is_instanceRef() const { return klass()->is_reference_instance_klass(); }
195 bool oopDesc::is_stackChunk() const { return klass()->is_stack_chunk_instance_klass(); }
196 bool oopDesc::is_array() const { return klass()->is_array_klass(); }
197 bool oopDesc::is_objArray() const { return klass()->is_objArray_klass(); }
198 bool oopDesc::is_typeArray() const { return klass()->is_typeArray_klass(); }
199
200 template<typename T>
201 T* oopDesc::field_addr(int offset) const { return reinterpret_cast<T*>(cast_from_oop<intptr_t>(as_oop()) + offset); }
202
203 template <typename T>
204 size_t oopDesc::field_offset(T* p) const { return pointer_delta((void*)p, (void*)this, 1); }
205
206 template <DecoratorSet decorators>
207 inline oop oopDesc::obj_field_access(int offset) const { return HeapAccess<decorators>::oop_load_at(as_oop(), offset); }
208 inline oop oopDesc::obj_field(int offset) const { return HeapAccess<>::oop_load_at(as_oop(), offset); }
209
210 inline void oopDesc::obj_field_put(int offset, oop value) { HeapAccess<>::oop_store_at(as_oop(), offset, value); }
211 template <DecoratorSet decorators>
212 inline void oopDesc::obj_field_put_access(int offset, oop value) { HeapAccess<decorators>::oop_store_at(as_oop(), offset, value); }
213
214 inline jbyte oopDesc::byte_field(int offset) const { return *field_addr<jbyte>(offset); }
215 inline void oopDesc::byte_field_put(int offset, jbyte value) { *field_addr<jbyte>(offset) = value; }
216
217 inline jchar oopDesc::char_field(int offset) const { return *field_addr<jchar>(offset); }
218 inline void oopDesc::char_field_put(int offset, jchar value) { *field_addr<jchar>(offset) = value; }
219
220 inline jboolean oopDesc::bool_field(int offset) const { return *field_addr<jboolean>(offset); }
221 inline void oopDesc::bool_field_put(int offset, jboolean value) { *field_addr<jboolean>(offset) = jboolean(value & 1); }
222 inline jboolean oopDesc::bool_field_volatile(int offset) const { return RawAccess<MO_SEQ_CST>::load(field_addr<jboolean>(offset)); }
223 inline void oopDesc::bool_field_put_volatile(int offset, jboolean value) { RawAccess<MO_SEQ_CST>::store(field_addr<jboolean>(offset), jboolean(value & 1)); }
224 inline jshort oopDesc::short_field(int offset) const { return *field_addr<jshort>(offset); }
225 inline void oopDesc::short_field_put(int offset, jshort value) { *field_addr<jshort>(offset) = value; }
226
227 inline jint oopDesc::int_field(int offset) const { return *field_addr<jint>(offset); }
228 inline void oopDesc::int_field_put(int offset, jint value) { *field_addr<jint>(offset) = value; }
229
230 inline jlong oopDesc::long_field(int offset) const { return *field_addr<jlong>(offset); }
231 inline void oopDesc::long_field_put(int offset, jlong value) { *field_addr<jlong>(offset) = value; }
232
233 inline jfloat oopDesc::float_field(int offset) const { return *field_addr<jfloat>(offset); }
234 inline void oopDesc::float_field_put(int offset, jfloat value) { *field_addr<jfloat>(offset) = value; }
235
236 inline jdouble oopDesc::double_field(int offset) const { return *field_addr<jdouble>(offset); }
237 inline void oopDesc::double_field_put(int offset, jdouble value) { *field_addr<jdouble>(offset) = value; }
238
239 bool oopDesc::is_locked() const {
240 return mark().is_locked();
241 }
242
243 bool oopDesc::is_unlocked() const {
244 return mark().is_unlocked();
245 }
246
247 // Used only for markSweep, scavenging
248 bool oopDesc::is_gc_marked() const {
249 return mark().is_marked();
250 }
251
252 // Used by scavengers
253 bool oopDesc::is_forwarded() const {
254 // The extra heap check is needed since the obj might be locked, in which case the
255 // mark would point to a stack location and have the sentinel bit cleared
256 return mark().is_marked();
257 }
258
259 // Used by scavengers
260 void oopDesc::forward_to(oop p) {
261 verify_forwardee(p);
262 markWord m = markWord::encode_pointer_as_mark(p);
263 assert(m.decode_pointer() == p, "encoding must be reversible");
264 set_mark(m);
265 }
266
267 oop oopDesc::forward_to_atomic(oop p, markWord compare, atomic_memory_order order) {
268 verify_forwardee(p);
269 markWord m = markWord::encode_pointer_as_mark(p);
270 assert(m.decode_pointer() == p, "encoding must be reversible");
271 markWord old_mark = cas_set_mark(m, compare, order);
272 if (old_mark == compare) {
273 return NULL;
274 } else {
275 return cast_to_oop(old_mark.decode_pointer());
276 }
277 }
278
279 // Note that the forwardee is not the same thing as the displaced_mark.
280 // The forwardee is used when copying during scavenge and mark-sweep.
281 // It does need to clear the low two locking- and GC-related bits.
282 oop oopDesc::forwardee() const {
283 assert(is_forwarded(), "only decode when actually forwarded");
284 return cast_to_oop(mark().decode_pointer());
285 }
286
287 // The following method needs to be MT safe.
288 uint oopDesc::age() const {
289 assert(!mark().is_marked(), "Attempt to read age from forwarded mark");
290 if (has_displaced_mark()) {
291 return displaced_mark().age();
292 } else {
293 return mark().age();
294 }
295 }
296
297 void oopDesc::incr_age() {
298 assert(!mark().is_marked(), "Attempt to increment age of forwarded mark");
299 if (has_displaced_mark()) {
300 set_displaced_mark(displaced_mark().incr_age());
301 } else {
302 set_mark(mark().incr_age());
303 }
304 }
305
306 template <typename OopClosureType>
307 void oopDesc::oop_iterate(OopClosureType* cl) {
308 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass());
309 }
310
311 template <typename OopClosureType>
312 void oopDesc::oop_iterate(OopClosureType* cl, MemRegion mr) {
313 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass(), mr);
314 }
315
316 template <typename OopClosureType>
317 size_t oopDesc::oop_iterate_size(OopClosureType* cl) {
318 Klass* k = klass();
319 size_t size = size_given_klass(k);
320 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k);
321 return size;
322 }
323
324 template <typename OopClosureType>
325 size_t oopDesc::oop_iterate_size(OopClosureType* cl, MemRegion mr) {
326 Klass* k = klass();
327 size_t size = size_given_klass(k);
328 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k, mr);
329 return size;
330 }
331
332 template <typename OopClosureType>
333 void oopDesc::oop_iterate_backwards(OopClosureType* cl) {
334 oop_iterate_backwards(cl, klass());
335 }
336
337 template <typename OopClosureType>
338 void oopDesc::oop_iterate_backwards(OopClosureType* cl, Klass* k) {
339 assert(k == klass(), "wrong klass");
340 OopIteratorClosureDispatch::oop_oop_iterate_backwards(cl, this, k);
341 }
342
343 bool oopDesc::is_instanceof_or_null(oop obj, Klass* klass) {
344 return obj == NULL || obj->klass()->is_subtype_of(klass);
345 }
346
347 intptr_t oopDesc::identity_hash() {
348 // Fast case; if the object is unlocked and the hash value is set, no locking is needed
349 // Note: The mark must be read into local variable to avoid concurrent updates.
350 markWord mrk = mark();
351 if (mrk.is_unlocked() && !mrk.has_no_hash()) {
352 return mrk.hash();
353 } else if (mrk.is_marked()) {
354 return mrk.hash();
355 } else {
356 return slow_identity_hash();
357 }
358 }
359
360 // This checks fast simple case of whether the oop has_no_hash,
361 // to optimize JVMTI table lookup.
362 bool oopDesc::fast_no_hash_check() {
363 markWord mrk = mark_acquire();
364 assert(!mrk.is_marked(), "should never be marked");
365 return mrk.is_unlocked() && mrk.has_no_hash();
366 }
367
368 bool oopDesc::has_displaced_mark() const {
369 return mark().has_displaced_mark_helper();
370 }
371
372 markWord oopDesc::displaced_mark() const {
373 return mark().displaced_mark_helper();
374 }
375
376 void oopDesc::set_displaced_mark(markWord m) {
377 mark().set_displaced_mark_helper(m);
378 }
379
380 bool oopDesc::mark_must_be_preserved() const {
381 return mark_must_be_preserved(mark());
382 }
383
384 bool oopDesc::mark_must_be_preserved(markWord m) const {
385 return m.must_be_preserved(this);
386 }
387
388 #endif // SHARE_OOPS_OOP_INLINE_HPP