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
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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,
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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/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(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(markWord::prototype());
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 template<typename T>
213 T* oopDesc::field_addr(int offset) const { return reinterpret_cast<T*>(cast_from_oop<intptr_t>(as_oop()) + offset); }
214
215 template <typename T>
216 size_t oopDesc::field_offset(T* p) const { return pointer_delta((void*)p, (void*)this, 1); }
217
218 template <DecoratorSet decorators>
219 inline oop oopDesc::obj_field_access(int offset) const { return HeapAccess<decorators>::oop_load_at(as_oop(), offset); }
220 inline oop oopDesc::obj_field(int offset) const { return HeapAccess<>::oop_load_at(as_oop(), offset); }
221
222 inline void oopDesc::obj_field_put(int offset, oop value) { HeapAccess<>::oop_store_at(as_oop(), offset, value); }
223 template <DecoratorSet decorators>
224 inline void oopDesc::obj_field_put_access(int offset, oop value) { HeapAccess<decorators>::oop_store_at(as_oop(), offset, value); }
225
226 inline jbyte oopDesc::byte_field(int offset) const { return *field_addr<jbyte>(offset); }
227 inline void oopDesc::byte_field_put(int offset, jbyte value) { *field_addr<jbyte>(offset) = value; }
228
229 inline jchar oopDesc::char_field(int offset) const { return *field_addr<jchar>(offset); }
230 inline void oopDesc::char_field_put(int offset, jchar value) { *field_addr<jchar>(offset) = value; }
231
232 inline jboolean oopDesc::bool_field(int offset) const { return *field_addr<jboolean>(offset); }
233 inline void oopDesc::bool_field_put(int offset, jboolean value) { *field_addr<jboolean>(offset) = jboolean(value & 1); }
234 inline jboolean oopDesc::bool_field_volatile(int offset) const { return RawAccess<MO_SEQ_CST>::load(field_addr<jboolean>(offset)); }
235 inline void oopDesc::bool_field_put_volatile(int offset, jboolean value) { RawAccess<MO_SEQ_CST>::store(field_addr<jboolean>(offset), jboolean(value & 1)); }
236 inline jshort oopDesc::short_field(int offset) const { return *field_addr<jshort>(offset); }
237 inline void oopDesc::short_field_put(int offset, jshort value) { *field_addr<jshort>(offset) = value; }
238
239 inline jint oopDesc::int_field(int offset) const { return *field_addr<jint>(offset); }
240 inline void oopDesc::int_field_put(int offset, jint value) { *field_addr<jint>(offset) = value; }
241 inline jint oopDesc::int_field_relaxed(int offset) const { return Atomic::load(field_addr<jint>(offset)); }
242 inline void oopDesc::int_field_put_relaxed(int offset, jint value) { Atomic::store(field_addr<jint>(offset), value); }
243
244 inline jlong oopDesc::long_field(int offset) const { return *field_addr<jlong>(offset); }
245 inline void oopDesc::long_field_put(int offset, jlong value) { *field_addr<jlong>(offset) = value; }
246
247 inline jfloat oopDesc::float_field(int offset) const { return *field_addr<jfloat>(offset); }
248 inline void oopDesc::float_field_put(int offset, jfloat value) { *field_addr<jfloat>(offset) = value; }
249
250 inline jdouble oopDesc::double_field(int offset) const { return *field_addr<jdouble>(offset); }
251 inline void oopDesc::double_field_put(int offset, jdouble value) { *field_addr<jdouble>(offset) = value; }
252
253 bool oopDesc::is_locked() const {
254 return mark().is_locked();
255 }
256
257 bool oopDesc::is_unlocked() const {
258 return mark().is_unlocked();
259 }
260
261 // Used only for markSweep, scavenging
262 bool oopDesc::is_gc_marked() const {
263 return mark().is_marked();
264 }
265
266 // Used by scavengers
267 bool oopDesc::is_forwarded() const {
268 // The extra heap check is needed since the obj might be locked, in which case the
269 // mark would point to a stack location and have the sentinel bit cleared
270 return mark().is_marked();
271 }
272
273 // Used by scavengers
274 void oopDesc::forward_to(oop p) {
275 markWord m = markWord::encode_pointer_as_mark(p);
276 assert(m.decode_pointer() == p, "encoding must be reversible");
277 set_mark(m);
278 }
279
280 oop oopDesc::forward_to_atomic(oop p, markWord compare, atomic_memory_order order) {
281 markWord m = markWord::encode_pointer_as_mark(p);
282 assert(m.decode_pointer() == p, "encoding must be reversible");
283 markWord old_mark = cas_set_mark(m, compare, order);
284 if (old_mark == compare) {
285 return nullptr;
286 } else {
287 return cast_to_oop(old_mark.decode_pointer());
288 }
289 }
290
291 // Note that the forwardee is not the same thing as the displaced_mark.
292 // The forwardee is used when copying during scavenge and mark-sweep.
293 // It does need to clear the low two locking- and GC-related bits.
294 oop oopDesc::forwardee() const {
295 assert(is_forwarded(), "only decode when actually forwarded");
296 return cast_to_oop(mark().decode_pointer());
297 }
298
299 // The following method needs to be MT safe.
300 uint oopDesc::age() const {
301 assert(!mark().is_marked(), "Attempt to read age from forwarded mark");
302 if (has_displaced_mark()) {
303 return displaced_mark().age();
304 } else {
305 return mark().age();
306 }
307 }
308
309 void oopDesc::incr_age() {
310 assert(!mark().is_marked(), "Attempt to increment age of forwarded mark");
311 if (has_displaced_mark()) {
312 set_displaced_mark(displaced_mark().incr_age());
313 } else {
314 set_mark(mark().incr_age());
315 }
316 }
317
318 template <typename OopClosureType>
319 void oopDesc::oop_iterate(OopClosureType* cl) {
320 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass());
321 }
322
323 template <typename OopClosureType>
324 void oopDesc::oop_iterate(OopClosureType* cl, MemRegion mr) {
325 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass(), mr);
326 }
327
328 template <typename OopClosureType>
329 size_t oopDesc::oop_iterate_size(OopClosureType* cl) {
330 Klass* k = klass();
331 size_t size = size_given_klass(k);
332 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k);
333 return size;
334 }
335
336 template <typename OopClosureType>
337 size_t oopDesc::oop_iterate_size(OopClosureType* cl, MemRegion mr) {
338 Klass* k = klass();
339 size_t size = size_given_klass(k);
340 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k, mr);
341 return size;
342 }
343
344 template <typename OopClosureType>
345 void oopDesc::oop_iterate_backwards(OopClosureType* cl) {
346 oop_iterate_backwards(cl, klass());
347 }
348
349 template <typename OopClosureType>
350 void oopDesc::oop_iterate_backwards(OopClosureType* cl, Klass* k) {
351 assert(k == klass(), "wrong klass");
352 OopIteratorClosureDispatch::oop_oop_iterate_backwards(cl, this, k);
353 }
354
355 bool oopDesc::is_instanceof_or_null(oop obj, Klass* klass) {
356 return obj == nullptr || obj->klass()->is_subtype_of(klass);
357 }
358
359 intptr_t oopDesc::identity_hash() {
360 // Fast case; if the object is unlocked and the hash value is set, no locking is needed
361 // Note: The mark must be read into local variable to avoid concurrent updates.
362 markWord mrk = mark();
363 if (mrk.is_unlocked() && !mrk.has_no_hash()) {
364 return mrk.hash();
365 } else if (mrk.is_marked()) {
366 return mrk.hash();
367 } else {
368 return slow_identity_hash();
369 }
370 }
371
372 // This checks fast simple case of whether the oop has_no_hash,
373 // to optimize JVMTI table lookup.
374 bool oopDesc::fast_no_hash_check() {
375 markWord mrk = mark_acquire();
376 assert(!mrk.is_marked(), "should never be marked");
377 return mrk.is_unlocked() && mrk.has_no_hash();
378 }
379
380 bool oopDesc::has_displaced_mark() const {
381 return mark().has_displaced_mark_helper();
382 }
383
384 markWord oopDesc::displaced_mark() const {
385 return mark().displaced_mark_helper();
386 }
387
388 void oopDesc::set_displaced_mark(markWord m) {
389 mark().set_displaced_mark_helper(m);
390 }
391
392 bool oopDesc::mark_must_be_preserved() const {
393 return mark_must_be_preserved(mark());
394 }
395
396 bool oopDesc::mark_must_be_preserved(markWord m) const {
397 return m.must_be_preserved(this);
398 }
399
400 #endif // SHARE_OOPS_OOP_INLINE_HPP