1 /*
2 * Copyright (c) 1997, 2022, 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.
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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/instanceKlass.hpp"
36 #include "oops/markWord.hpp"
37 #include "oops/oopsHierarchy.hpp"
38 #include "runtime/atomic.hpp"
39 #include "runtime/globals.hpp"
40 #include "utilities/align.hpp"
41 #include "utilities/debug.hpp"
42 #include "utilities/macros.hpp"
43 #include "utilities/globalDefinitions.hpp"
44
45 // Implementation of all inlined member functions defined in oop.hpp
46 // We need a separate file to avoid circular references
47
48 markWord oopDesc::mark() const {
49 return Atomic::load(&_mark);
50 }
51
52 markWord oopDesc::mark_acquire() const {
53 return Atomic::load_acquire(&_mark);
54 }
55
56 markWord* oopDesc::mark_addr() const {
57 return (markWord*) &_mark;
58 }
59
60 void oopDesc::set_mark(markWord m) {
61 Atomic::store(&_mark, m);
62 }
63
64 void oopDesc::set_mark(HeapWord* mem, markWord m) {
65 *(markWord*)(((char*)mem) + mark_offset_in_bytes()) = m;
66 }
67
68 void oopDesc::release_set_mark(markWord m) {
69 Atomic::release_store(&_mark, m);
70 }
71
72 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark) {
73 return Atomic::cmpxchg(&_mark, old_mark, new_mark);
74 }
75
76 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark, atomic_memory_order order) {
77 return Atomic::cmpxchg(&_mark, old_mark, new_mark, order);
78 }
79
80 void oopDesc::init_mark() {
81 set_mark(markWord::prototype());
82 }
83
84 Klass* oopDesc::klass() const {
85 if (UseCompressedClassPointers) {
86 return CompressedKlassPointers::decode_not_null(_metadata._compressed_klass);
87 } else {
88 return _metadata._klass;
89 }
90 }
91
92 Klass* oopDesc::klass_or_null() const {
93 if (UseCompressedClassPointers) {
94 return CompressedKlassPointers::decode(_metadata._compressed_klass);
95 } else {
96 return _metadata._klass;
97 }
98 }
99
100 Klass* oopDesc::klass_or_null_acquire() const {
101 if (UseCompressedClassPointers) {
102 narrowKlass nklass = Atomic::load_acquire(&_metadata._compressed_klass);
103 return CompressedKlassPointers::decode(nklass);
104 } else {
105 return Atomic::load_acquire(&_metadata._klass);
106 }
107 }
108
109 void oopDesc::set_klass(Klass* k) {
110 assert(Universe::is_bootstrapping() || (k != NULL && k->is_klass()), "incorrect Klass");
111 if (UseCompressedClassPointers) {
112 _metadata._compressed_klass = CompressedKlassPointers::encode_not_null(k);
113 } else {
114 _metadata._klass = k;
115 }
116 }
117
118 void oopDesc::release_set_klass(HeapWord* mem, Klass* k) {
119 assert(Universe::is_bootstrapping() || (k != NULL && k->is_klass()), "incorrect Klass");
120 char* raw_mem = ((char*)mem + klass_offset_in_bytes());
121 if (UseCompressedClassPointers) {
122 Atomic::release_store((narrowKlass*)raw_mem,
123 CompressedKlassPointers::encode_not_null(k));
124 } else {
125 Atomic::release_store((Klass**)raw_mem, k);
126 }
127 }
128
129 void oopDesc::set_klass_gap(HeapWord* mem, int v) {
130 if (UseCompressedClassPointers) {
131 *(int*)(((char*)mem) + klass_gap_offset_in_bytes()) = v;
132 }
133 }
134
135 bool oopDesc::is_a(Klass* k) const {
136 return klass()->is_subtype_of(k);
137 }
138
139 size_t oopDesc::size() {
140 return size_given_klass(klass());
141 }
142
143 size_t oopDesc::size_given_klass(Klass* klass) {
144 int lh = klass->layout_helper();
145 size_t s;
146
147 // lh is now a value computed at class initialization that may hint
148 // at the size. For instances, this is positive and equal to the
149 // size. For arrays, this is negative and provides log2 of the
150 // array element size. For other oops, it is zero and thus requires
151 // a virtual call.
152 //
153 // We go to all this trouble because the size computation is at the
154 // heart of phase 2 of mark-compaction, and called for every object,
155 // alive or dead. So the speed here is equal in importance to the
156 // speed of allocation.
157
158 if (lh > Klass::_lh_neutral_value) {
159 if (!Klass::layout_helper_needs_slow_path(lh)) {
160 s = lh >> LogHeapWordSize; // deliver size scaled by wordSize
161 } else {
162 s = klass->oop_size(this);
163 }
164 } else if (lh <= Klass::_lh_neutral_value) {
165 // The most common case is instances; fall through if so.
166 if (lh < Klass::_lh_neutral_value) {
167 // Second most common case is arrays. We have to fetch the
168 // length of the array, shift (multiply) it appropriately,
169 // up to wordSize, add the header, and align to object size.
170 size_t size_in_bytes;
171 size_t array_length = (size_t) ((arrayOop)this)->length();
172 size_in_bytes = array_length << Klass::layout_helper_log2_element_size(lh);
173 size_in_bytes += Klass::layout_helper_header_size(lh);
174
175 // This code could be simplified, but by keeping array_header_in_bytes
176 // in units of bytes and doing it this way we can round up just once,
177 // skipping the intermediate round to HeapWordSize.
178 s = align_up(size_in_bytes, MinObjAlignmentInBytes) / HeapWordSize;
179
180 assert(s == klass->oop_size(this) || size_might_change(), "wrong array object size");
181 } else {
182 // Must be zero, so bite the bullet and take the virtual call.
183 s = klass->oop_size(this);
184 }
185 }
186
187 assert(s > 0, "Oop size must be greater than zero, not " SIZE_FORMAT, s);
188 assert(is_object_aligned(s), "Oop size is not properly aligned: " SIZE_FORMAT, s);
189 return s;
190 }
191
192 bool oopDesc::is_instance() const { return klass()->is_instance_klass(); }
193 bool oopDesc::is_instanceRef() const { return klass()->is_reference_instance_klass(); }
194 bool oopDesc::is_stackChunk() const { return klass()->is_stack_chunk_instance_klass(); }
195 bool oopDesc::is_array() const { return klass()->is_array_klass(); }
196 bool oopDesc::is_objArray() const { return klass()->is_objArray_klass(); }
197 bool oopDesc::is_typeArray() const { return klass()->is_typeArray_klass(); }
198
199 template<typename T>
200 T* oopDesc::field_addr(int offset) const { return reinterpret_cast<T*>(cast_from_oop<intptr_t>(as_oop()) + offset); }
201
202 template <typename T>
203 size_t oopDesc::field_offset(T* p) const { return pointer_delta((void*)p, (void*)this, 1); }
204
205 template <DecoratorSet decorators>
206 inline oop oopDesc::obj_field_access(int offset) const { return HeapAccess<decorators>::oop_load_at(as_oop(), offset); }
207 inline oop oopDesc::obj_field(int offset) const { return HeapAccess<>::oop_load_at(as_oop(), offset); }
208
209 inline void oopDesc::obj_field_put(int offset, oop value) { HeapAccess<>::oop_store_at(as_oop(), offset, value); }
210 template <DecoratorSet decorators>
211 inline void oopDesc::obj_field_put_access(int offset, oop value) { HeapAccess<decorators>::oop_store_at(as_oop(), offset, value); }
212
213 inline jbyte oopDesc::byte_field(int offset) const { return *field_addr<jbyte>(offset); }
214 inline void oopDesc::byte_field_put(int offset, jbyte value) { *field_addr<jbyte>(offset) = value; }
215
216 inline jchar oopDesc::char_field(int offset) const { return *field_addr<jchar>(offset); }
217 inline void oopDesc::char_field_put(int offset, jchar value) { *field_addr<jchar>(offset) = value; }
218
219 inline jboolean oopDesc::bool_field(int offset) const { return *field_addr<jboolean>(offset); }
220 inline void oopDesc::bool_field_put(int offset, jboolean value) { *field_addr<jboolean>(offset) = jboolean(value & 1); }
221 inline jboolean oopDesc::bool_field_volatile(int offset) const { return RawAccess<MO_SEQ_CST>::load(field_addr<jboolean>(offset)); }
222 inline void oopDesc::bool_field_put_volatile(int offset, jboolean value) { RawAccess<MO_SEQ_CST>::store(field_addr<jboolean>(offset), jboolean(value & 1)); }
223 inline jshort oopDesc::short_field(int offset) const { return *field_addr<jshort>(offset); }
224 inline void oopDesc::short_field_put(int offset, jshort value) { *field_addr<jshort>(offset) = value; }
225
226 inline jint oopDesc::int_field(int offset) const { return *field_addr<jint>(offset); }
227 inline void oopDesc::int_field_put(int offset, jint value) { *field_addr<jint>(offset) = value; }
228
229 inline jlong oopDesc::long_field(int offset) const { return *field_addr<jlong>(offset); }
230 inline void oopDesc::long_field_put(int offset, jlong value) { *field_addr<jlong>(offset) = value; }
231
232 inline jfloat oopDesc::float_field(int offset) const { return *field_addr<jfloat>(offset); }
233 inline void oopDesc::float_field_put(int offset, jfloat value) { *field_addr<jfloat>(offset) = value; }
234
235 inline jdouble oopDesc::double_field(int offset) const { return *field_addr<jdouble>(offset); }
236 inline void oopDesc::double_field_put(int offset, jdouble value) { *field_addr<jdouble>(offset) = value; }
237
238 bool oopDesc::is_locked() const {
239 return mark().is_locked();
240 }
241
242 bool oopDesc::is_unlocked() const {
243 return mark().is_unlocked();
244 }
245
246 // Used only for markSweep, scavenging
247 bool oopDesc::is_gc_marked() const {
248 return mark().is_marked();
249 }
250
251 // Used by scavengers
252 bool oopDesc::is_forwarded() const {
253 // The extra heap check is needed since the obj might be locked, in which case the
254 // mark would point to a stack location and have the sentinel bit cleared
255 return mark().is_marked();
256 }
257
258 // Used by scavengers
259 void oopDesc::forward_to(oop p) {
260 verify_forwardee(p);
261 markWord m = markWord::encode_pointer_as_mark(p);
262 assert(m.decode_pointer() == p, "encoding must be reversible");
263 set_mark(m);
264 }
265
266 oop oopDesc::forward_to_atomic(oop p, markWord compare, atomic_memory_order order) {
267 verify_forwardee(p);
268 markWord m = markWord::encode_pointer_as_mark(p);
269 assert(m.decode_pointer() == p, "encoding must be reversible");
270 markWord old_mark = cas_set_mark(m, compare, order);
271 if (old_mark == compare) {
272 return NULL;
273 } else {
274 return cast_to_oop(old_mark.decode_pointer());
275 }
276 }
277
278 // Note that the forwardee is not the same thing as the displaced_mark.
279 // The forwardee is used when copying during scavenge and mark-sweep.
280 // It does need to clear the low two locking- and GC-related bits.
281 oop oopDesc::forwardee() const {
282 assert(is_forwarded(), "only decode when actually forwarded");
283 return cast_to_oop(mark().decode_pointer());
284 }
285
286 // The following method needs to be MT safe.
287 uint oopDesc::age() const {
288 assert(!mark().is_marked(), "Attempt to read age from forwarded mark");
289 if (has_displaced_mark()) {
290 return displaced_mark().age();
291 } else {
292 return mark().age();
293 }
294 }
295
296 void oopDesc::incr_age() {
297 assert(!mark().is_marked(), "Attempt to increment age of forwarded mark");
298 if (has_displaced_mark()) {
299 set_displaced_mark(displaced_mark().incr_age());
300 } else {
301 set_mark(mark().incr_age());
302 }
303 }
304
305 template <typename OopClosureType>
306 void oopDesc::oop_iterate(OopClosureType* cl) {
307 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass());
308 }
309
310 template <typename OopClosureType>
311 void oopDesc::oop_iterate(OopClosureType* cl, MemRegion mr) {
312 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass(), mr);
313 }
314
315 template <typename OopClosureType>
316 size_t oopDesc::oop_iterate_size(OopClosureType* cl) {
317 Klass* k = klass();
318 size_t size = size_given_klass(k);
319 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k);
320 return size;
321 }
322
323 template <typename OopClosureType>
324 size_t oopDesc::oop_iterate_size(OopClosureType* cl, MemRegion mr) {
325 Klass* k = klass();
326 size_t size = size_given_klass(k);
327 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k, mr);
328 return size;
329 }
330
331 template <typename OopClosureType>
332 void oopDesc::oop_iterate_backwards(OopClosureType* cl) {
333 oop_iterate_backwards(cl, klass());
334 }
335
336 template <typename OopClosureType>
337 void oopDesc::oop_iterate_backwards(OopClosureType* cl, Klass* k) {
338 assert(k == klass(), "wrong klass");
339 OopIteratorClosureDispatch::oop_oop_iterate_backwards(cl, this, k);
340 }
341
342 bool oopDesc::is_instanceof_or_null(oop obj, Klass* klass) {
343 return obj == NULL || obj->klass()->is_subtype_of(klass);
344 }
345
346 intptr_t oopDesc::identity_hash() {
347 // Fast case; if the object is unlocked and the hash value is set, no locking is needed
348 // Note: The mark must be read into local variable to avoid concurrent updates.
349 markWord mrk = mark();
350 if (mrk.is_unlocked() && !mrk.has_no_hash()) {
351 return mrk.hash();
352 } else if (mrk.is_marked()) {
353 return mrk.hash();
354 } else {
355 return slow_identity_hash();
356 }
357 }
358
359 // This checks fast simple case of whether the oop has_no_hash,
360 // to optimize JVMTI table lookup.
361 bool oopDesc::fast_no_hash_check() {
362 markWord mrk = mark_acquire();
363 assert(!mrk.is_marked(), "should never be marked");
364 return mrk.is_unlocked() && mrk.has_no_hash();
365 }
366
367 bool oopDesc::has_displaced_mark() const {
368 return mark().has_displaced_mark_helper();
369 }
370
371 markWord oopDesc::displaced_mark() const {
372 return mark().displaced_mark_helper();
373 }
374
375 void oopDesc::set_displaced_mark(markWord m) {
376 mark().set_displaced_mark_helper(m);
377 }
378
379 bool oopDesc::mark_must_be_preserved() const {
380 return mark_must_be_preserved(mark());
381 }
382
383 bool oopDesc::mark_must_be_preserved(markWord m) const {
384 return m.must_be_preserved(this);
385 }
386
387 #endif // SHARE_OOPS_OOP_INLINE_HPP