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.
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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
21 * questions.
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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 "memory/iterator.inline.hpp"
32 #include "oops/access.inline.hpp"
33 #include "oops/arrayKlass.hpp"
34 #include "oops/arrayOop.hpp"
35 #include "oops/compressedKlass.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(HeapWord* mem, markWord m) {
70 Atomic::release_store((markWord*)(((char*)mem) + mark_offset_in_bytes()), m);
71 }
72
73 void oopDesc::release_set_mark(markWord m) {
74 Atomic::release_store(&_mark, m);
75 }
76
77 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark) {
78 return Atomic::cmpxchg(&_mark, old_mark, new_mark);
79 }
80
81 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark, atomic_memory_order order) {
82 return Atomic::cmpxchg(&_mark, old_mark, new_mark, order);
83 }
84
85 void oopDesc::init_mark() {
86 set_mark(Klass::default_prototype_header(klass()));
87 }
88
89 Klass* oopDesc::klass() const {
90 if (UseCompressedClassPointers) {
91 return CompressedKlassPointers::decode_not_null(_metadata._compressed_klass);
92 } else {
93 return _metadata._klass;
94 }
95 }
96
97 Klass* oopDesc::klass_or_null() const {
98 if (UseCompressedClassPointers) {
99 return CompressedKlassPointers::decode(_metadata._compressed_klass);
100 } else {
101 return _metadata._klass;
102 }
103 }
104
105 Klass* oopDesc::klass_or_null_acquire() const {
106 if (UseCompressedClassPointers) {
107 narrowKlass nklass = Atomic::load_acquire(&_metadata._compressed_klass);
108 return CompressedKlassPointers::decode(nklass);
109 } else {
110 return Atomic::load_acquire(&_metadata._klass);
111 }
112 }
113
114 Klass* oopDesc::klass_raw() const {
115 if (UseCompressedClassPointers) {
116 return CompressedKlassPointers::decode_raw(_metadata._compressed_klass);
117 } else {
118 return _metadata._klass;
119 }
120 }
121
122 void oopDesc::set_klass(Klass* k) {
123 assert(Universe::is_bootstrapping() || (k != nullptr && k->is_klass()), "incorrect Klass");
124 if (UseCompressedClassPointers) {
125 _metadata._compressed_klass = CompressedKlassPointers::encode_not_null(k);
126 } else {
127 _metadata._klass = k;
128 }
129 }
130
131 void oopDesc::release_set_klass(HeapWord* mem, Klass* k) {
132 assert(Universe::is_bootstrapping() || (k != nullptr && k->is_klass()), "incorrect Klass");
133 char* raw_mem = ((char*)mem + klass_offset_in_bytes());
134 if (UseCompressedClassPointers) {
135 Atomic::release_store((narrowKlass*)raw_mem,
136 CompressedKlassPointers::encode_not_null(k));
137 } else {
138 Atomic::release_store((Klass**)raw_mem, k);
139 }
140 }
141
142 void oopDesc::set_klass_gap(HeapWord* mem, int v) {
143 if (UseCompressedClassPointers) {
144 *(int*)(((char*)mem) + klass_gap_offset_in_bytes()) = v;
145 }
146 }
147
148 bool oopDesc::is_a(Klass* k) const {
149 return klass()->is_subtype_of(k);
150 }
151
152 size_t oopDesc::size() {
153 return size_given_klass(klass());
154 }
155
156 size_t oopDesc::size_given_klass(Klass* klass) {
157 int lh = klass->layout_helper();
158 size_t s;
159
160 // lh is now a value computed at class initialization that may hint
161 // at the size. For instances, this is positive and equal to the
162 // size. For arrays, this is negative and provides log2 of the
163 // array element size. For other oops, it is zero and thus requires
164 // a virtual call.
165 //
166 // We go to all this trouble because the size computation is at the
167 // heart of phase 2 of mark-compaction, and called for every object,
168 // alive or dead. So the speed here is equal in importance to the
169 // speed of allocation.
170
171 if (lh > Klass::_lh_neutral_value) {
172 if (!Klass::layout_helper_needs_slow_path(lh)) {
173 s = lh >> LogHeapWordSize; // deliver size scaled by wordSize
174 } else {
175 s = klass->oop_size(this);
176 }
177 } else if (lh <= Klass::_lh_neutral_value) {
178 // The most common case is instances; fall through if so.
179 if (lh < Klass::_lh_neutral_value) {
180 // Second most common case is arrays. We have to fetch the
181 // length of the array, shift (multiply) it appropriately,
182 // up to wordSize, add the header, and align to object size.
183 size_t size_in_bytes;
184 size_t array_length = (size_t) ((arrayOop)this)->length();
185 size_in_bytes = array_length << Klass::layout_helper_log2_element_size(lh);
186 size_in_bytes += Klass::layout_helper_header_size(lh);
187
188 // This code could be simplified, but by keeping array_header_in_bytes
189 // in units of bytes and doing it this way we can round up just once,
190 // skipping the intermediate round to HeapWordSize.
191 s = align_up(size_in_bytes, MinObjAlignmentInBytes) / HeapWordSize;
192
193 assert(s == klass->oop_size(this) || size_might_change(), "wrong array object size");
194 } else {
195 // Must be zero, so bite the bullet and take the virtual call.
196 s = klass->oop_size(this);
197 }
198 }
199
200 assert(s > 0, "Oop size must be greater than zero, not " SIZE_FORMAT, s);
201 assert(is_object_aligned(s), "Oop size is not properly aligned: " SIZE_FORMAT, s);
202 return s;
203 }
204
205 bool oopDesc::is_instance() const { return klass()->is_instance_klass(); }
206 bool oopDesc::is_instanceRef() const { return klass()->is_reference_instance_klass(); }
207 bool oopDesc::is_stackChunk() const { return klass()->is_stack_chunk_instance_klass(); }
208 bool oopDesc::is_array() const { return klass()->is_array_klass(); }
209 bool oopDesc::is_objArray() const { return klass()->is_objArray_klass(); }
210 bool oopDesc::is_typeArray() const { return klass()->is_typeArray_klass(); }
211
212 bool oopDesc::is_inline_type() const { return mark().is_inline_type(); }
213 #ifdef _LP64
214 bool oopDesc::is_flatArray() const {
215 markWord mrk = mark();
216 return (mrk.is_unlocked()) ? mrk.is_flat_array() : klass()->is_flatArray_klass();
217 }
218 bool oopDesc::is_null_free_array() const {
219 markWord mrk = mark();
220 return (mrk.is_unlocked()) ? mrk.is_null_free_array() : klass()->is_null_free_array_klass();
221 }
222 #else
223 bool oopDesc::is_flatArray() const { return klass()->is_flatArray_klass(); }
224 bool oopDesc::is_null_free_array() const { return klass()->is_null_free_array_klass(); }
225 #endif
226
227 template<typename T>
228 T* oopDesc::field_addr(int offset) const { return reinterpret_cast<T*>(cast_from_oop<intptr_t>(as_oop()) + offset); }
229
230 template <typename T>
231 size_t oopDesc::field_offset(T* p) const { return pointer_delta((void*)p, (void*)this, 1); }
232
233 template <DecoratorSet decorators>
234 inline oop oopDesc::obj_field_access(int offset) const { return HeapAccess<decorators>::oop_load_at(as_oop(), offset); }
235 inline oop oopDesc::obj_field(int offset) const { return HeapAccess<>::oop_load_at(as_oop(), offset); }
236
237 inline void oopDesc::obj_field_put(int offset, oop value) { HeapAccess<>::oop_store_at(as_oop(), offset, value); }
238 template <DecoratorSet decorators>
239 inline void oopDesc::obj_field_put_access(int offset, oop value) { HeapAccess<decorators>::oop_store_at(as_oop(), offset, value); }
240
241 inline jbyte oopDesc::byte_field(int offset) const { return *field_addr<jbyte>(offset); }
242 inline void oopDesc::byte_field_put(int offset, jbyte value) { *field_addr<jbyte>(offset) = value; }
243
244 inline jchar oopDesc::char_field(int offset) const { return *field_addr<jchar>(offset); }
245 inline void oopDesc::char_field_put(int offset, jchar value) { *field_addr<jchar>(offset) = value; }
246
247 inline jboolean oopDesc::bool_field(int offset) const { return *field_addr<jboolean>(offset); }
248 inline void oopDesc::bool_field_put(int offset, jboolean value) { *field_addr<jboolean>(offset) = jboolean(value & 1); }
249 inline jboolean oopDesc::bool_field_volatile(int offset) const { return RawAccess<MO_SEQ_CST>::load(field_addr<jboolean>(offset)); }
250 inline void oopDesc::bool_field_put_volatile(int offset, jboolean value) { RawAccess<MO_SEQ_CST>::store(field_addr<jboolean>(offset), jboolean(value & 1)); }
251 inline jshort oopDesc::short_field(int offset) const { return *field_addr<jshort>(offset); }
252 inline void oopDesc::short_field_put(int offset, jshort value) { *field_addr<jshort>(offset) = value; }
253
254 inline jint oopDesc::int_field(int offset) const { return *field_addr<jint>(offset); }
255 inline void oopDesc::int_field_put(int offset, jint value) { *field_addr<jint>(offset) = value; }
256
257 inline jlong oopDesc::long_field(int offset) const { return *field_addr<jlong>(offset); }
258 inline void oopDesc::long_field_put(int offset, jlong value) { *field_addr<jlong>(offset) = value; }
259
260 inline jfloat oopDesc::float_field(int offset) const { return *field_addr<jfloat>(offset); }
261 inline void oopDesc::float_field_put(int offset, jfloat value) { *field_addr<jfloat>(offset) = value; }
262
263 inline jdouble oopDesc::double_field(int offset) const { return *field_addr<jdouble>(offset); }
264 inline void oopDesc::double_field_put(int offset, jdouble value) { *field_addr<jdouble>(offset) = value; }
265
266 bool oopDesc::is_locked() const {
267 return mark().is_locked();
268 }
269
270 bool oopDesc::is_unlocked() const {
271 return mark().is_unlocked();
272 }
273
274 // Used only for markSweep, scavenging
275 bool oopDesc::is_gc_marked() const {
276 return mark().is_marked();
277 }
278
279 // Used by scavengers
280 bool oopDesc::is_forwarded() const {
281 // The extra heap check is needed since the obj might be locked, in which case the
282 // mark would point to a stack location and have the sentinel bit cleared
283 return mark().is_marked();
284 }
285
286 // Used by scavengers
287 void oopDesc::forward_to(oop p) {
288 markWord m = markWord::encode_pointer_as_mark(p);
289 assert(m.decode_pointer() == p, "encoding must be reversible");
290 set_mark(m);
291 }
292
293 oop oopDesc::forward_to_atomic(oop p, markWord compare, atomic_memory_order order) {
294 markWord m = markWord::encode_pointer_as_mark(p);
295 assert(m.decode_pointer() == p, "encoding must be reversible");
296 markWord old_mark = cas_set_mark(m, compare, order);
297 if (old_mark == compare) {
298 return nullptr;
299 } else {
300 return cast_to_oop(old_mark.decode_pointer());
301 }
302 }
303
304 // Note that the forwardee is not the same thing as the displaced_mark.
305 // The forwardee is used when copying during scavenge and mark-sweep.
306 // It does need to clear the low two locking- and GC-related bits.
307 oop oopDesc::forwardee() const {
308 assert(is_forwarded(), "only decode when actually forwarded");
309 return cast_to_oop(mark().decode_pointer());
310 }
311
312 // The following method needs to be MT safe.
313 uint oopDesc::age() const {
314 markWord m = mark();
315 assert(!m.is_marked(), "Attempt to read age from forwarded mark");
316 if (m.has_displaced_mark_helper()) {
317 return m.displaced_mark_helper().age();
318 } else {
319 return m.age();
320 }
321 }
322
323 void oopDesc::incr_age() {
324 markWord m = mark();
325 assert(!m.is_marked(), "Attempt to increment age of forwarded mark");
326 if (m.has_displaced_mark_helper()) {
327 m.set_displaced_mark_helper(m.displaced_mark_helper().incr_age());
328 } else {
329 set_mark(m.incr_age());
330 }
331 }
332
333 template <typename OopClosureType>
334 void oopDesc::oop_iterate(OopClosureType* cl) {
335 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass());
336 }
337
338 template <typename OopClosureType>
339 void oopDesc::oop_iterate(OopClosureType* cl, MemRegion mr) {
340 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass(), mr);
341 }
342
343 template <typename OopClosureType>
344 size_t oopDesc::oop_iterate_size(OopClosureType* cl) {
345 Klass* k = klass();
346 size_t size = size_given_klass(k);
347 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k);
348 return size;
349 }
350
351 template <typename OopClosureType>
352 size_t oopDesc::oop_iterate_size(OopClosureType* cl, MemRegion mr) {
353 Klass* k = klass();
354 size_t size = size_given_klass(k);
355 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k, mr);
356 return size;
357 }
358
359 template <typename OopClosureType>
360 void oopDesc::oop_iterate_backwards(OopClosureType* cl) {
361 oop_iterate_backwards(cl, klass());
362 }
363
364 template <typename OopClosureType>
365 void oopDesc::oop_iterate_backwards(OopClosureType* cl, Klass* k) {
366 assert(k == klass(), "wrong klass");
367 OopIteratorClosureDispatch::oop_oop_iterate_backwards(cl, this, k);
368 }
369
370 bool oopDesc::is_instanceof_or_null(oop obj, Klass* klass) {
371 return obj == nullptr || obj->klass()->is_subtype_of(klass);
372 }
373
374 intptr_t oopDesc::identity_hash() {
375 // Fast case; if the object is unlocked and the hash value is set, no locking is needed
376 // Note: The mark must be read into local variable to avoid concurrent updates.
377 markWord mrk = mark();
378 if (mrk.is_unlocked() && !mrk.has_no_hash()) {
379 return mrk.hash();
380 } else if (mrk.is_marked()) {
381 return mrk.hash();
382 } else {
383 return slow_identity_hash();
384 }
385 }
386
387 // This checks fast simple case of whether the oop has_no_hash,
388 // to optimize JVMTI table lookup.
389 bool oopDesc::fast_no_hash_check() {
390 markWord mrk = mark_acquire();
391 assert(!mrk.is_marked(), "should never be marked");
392 return mrk.is_unlocked() && mrk.has_no_hash();
393 }
394
395 bool oopDesc::has_displaced_mark() const {
396 return mark().has_displaced_mark_helper();
397 }
398
399 markWord oopDesc::displaced_mark() const {
400 return mark().displaced_mark_helper();
401 }
402
403 void oopDesc::set_displaced_mark(markWord m) {
404 mark().set_displaced_mark_helper(m);
405 }
406
407 bool oopDesc::mark_must_be_preserved() const {
408 return mark_must_be_preserved(mark());
409 }
410
411 bool oopDesc::mark_must_be_preserved(markWord m) const {
412 return m.must_be_preserved(this);
413 }
414
415 #endif // SHARE_OOPS_OOP_INLINE_HPP