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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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.inline.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 uintptr_t v = HeapAccess<MO_RELAXED>::load_at(as_oop(), mark_offset_in_bytes());
49 return markWord(v);
50 }
51
52 markWord* oopDesc::mark_addr() const {
53 return (markWord*) &_mark;
54 }
55
56 void oopDesc::set_mark(markWord m) {
57 HeapAccess<MO_RELAXED>::store_at(as_oop(), mark_offset_in_bytes(), m.value());
58 }
59
60 void oopDesc::set_mark(HeapWord* mem, markWord m) {
61 *(markWord*)(((char*)mem) + mark_offset_in_bytes()) = m;
62 }
63
64 void oopDesc::release_set_mark(markWord m) {
65 HeapAccess<MO_RELEASE>::store_at(as_oop(), mark_offset_in_bytes(), m.value());
66 }
67
68 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark) {
69 uintptr_t v = HeapAccess<>::atomic_cmpxchg_at(as_oop(), mark_offset_in_bytes(), old_mark.value(), new_mark.value());
70 return markWord(v);
71 }
72
73 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark, atomic_memory_order order) {
74 return Atomic::cmpxchg(&_mark, old_mark, new_mark, order);
75 }
76
77 void oopDesc::init_mark() {
78 set_mark(markWord::prototype_for_klass(klass()));
79 }
80
81 Klass* oopDesc::klass() const {
82 if (UseCompressedClassPointers) {
83 return CompressedKlassPointers::decode_not_null(_metadata._compressed_klass);
84 } else {
85 return _metadata._klass;
86 }
87 }
88
89 Klass* oopDesc::klass_or_null() const {
90 if (UseCompressedClassPointers) {
91 return CompressedKlassPointers::decode(_metadata._compressed_klass);
92 } else {
93 return _metadata._klass;
94 }
95 }
96
97 Klass* oopDesc::klass_or_null_acquire() const {
98 if (UseCompressedClassPointers) {
99 narrowKlass nklass = Atomic::load_acquire(&_metadata._compressed_klass);
100 return CompressedKlassPointers::decode(nklass);
101 } else {
102 return Atomic::load_acquire(&_metadata._klass);
103 }
104 }
105
106 void oopDesc::set_klass(Klass* k) {
107 assert(Universe::is_bootstrapping() || (k != NULL && k->is_klass()), "incorrect Klass");
108 if (UseCompressedClassPointers) {
109 _metadata._compressed_klass = CompressedKlassPointers::encode_not_null(k);
110 } else {
111 _metadata._klass = k;
112 }
113 }
114
115 void oopDesc::release_set_klass(HeapWord* mem, Klass* k) {
116 assert(Universe::is_bootstrapping() || (k != NULL && k->is_klass()), "incorrect Klass");
117 char* raw_mem = ((char*)mem + klass_offset_in_bytes());
118 if (UseCompressedClassPointers) {
119 Atomic::release_store((narrowKlass*)raw_mem,
120 CompressedKlassPointers::encode_not_null(k));
121 } else {
122 Atomic::release_store((Klass**)raw_mem, k);
123 }
124 }
125
126 int oopDesc::klass_gap() const {
127 return *(int*)(((intptr_t)this) + klass_gap_offset_in_bytes());
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 void oopDesc::set_klass_gap(int v) {
137 set_klass_gap((HeapWord*)this, v);
138 }
139
140 bool oopDesc::is_a(Klass* k) const {
141 return klass()->is_subtype_of(k);
142 }
143
144 int oopDesc::size() {
145 return size_given_klass(klass());
146 }
147
148 int oopDesc::size_given_klass(Klass* klass) {
149 int lh = klass->layout_helper();
150 int s;
151
152 // lh is now a value computed at class initialization that may hint
153 // at the size. For instances, this is positive and equal to the
154 // size. For arrays, this is negative and provides log2 of the
155 // array element size. For other oops, it is zero and thus requires
156 // a virtual call.
157 //
158 // We go to all this trouble because the size computation is at the
159 // heart of phase 2 of mark-compaction, and called for every object,
160 // alive or dead. So the speed here is equal in importance to the
161 // speed of allocation.
162
163 if (lh > Klass::_lh_neutral_value) {
164 if (!Klass::layout_helper_needs_slow_path(lh)) {
165 s = lh >> LogHeapWordSize; // deliver size scaled by wordSize
166 } else {
167 s = klass->oop_size(this);
168 }
169 } else if (lh <= Klass::_lh_neutral_value) {
170 // The most common case is instances; fall through if so.
171 if (lh < Klass::_lh_neutral_value) {
172 // Second most common case is arrays. We have to fetch the
173 // length of the array, shift (multiply) it appropriately,
174 // up to wordSize, add the header, and align to object size.
175 size_t size_in_bytes;
176 size_t array_length = (size_t) ((arrayOop)this)->length();
177 size_in_bytes = array_length << Klass::layout_helper_log2_element_size(lh);
178 size_in_bytes += Klass::layout_helper_header_size(lh);
179
180 // This code could be simplified, but by keeping array_header_in_bytes
181 // in units of bytes and doing it this way we can round up just once,
182 // skipping the intermediate round to HeapWordSize.
183 s = (int)(align_up(size_in_bytes, MinObjAlignmentInBytes) / HeapWordSize);
184
185 // UseParallelGC and UseG1GC can change the length field
186 // of an "old copy" of an object array in the young gen so it indicates
187 // the grey portion of an already copied array. This will cause the first
188 // disjunct below to fail if the two comparands are computed across such
189 // a concurrent change.
190 assert((s == klass->oop_size(this)) ||
191 (Universe::is_gc_active() && is_objArray() && is_forwarded() && (get_UseParallelGC() || get_UseG1GC())),
192 "wrong array object size");
193 } else {
194 // Must be zero, so bite the bullet and take the virtual call.
195 s = klass->oop_size(this);
196 }
197 }
198
199 assert(s > 0, "Oop size must be greater than zero, not %d", s);
200 assert(is_object_aligned(s), "Oop size is not properly aligned: %d", s);
201 return s;
202 }
203
204 bool oopDesc::is_instance() const { return klass()->is_instance_klass(); }
205 bool oopDesc::is_array() const { return klass()->is_array_klass(); }
206 bool oopDesc::is_objArray() const { return klass()->is_objArray_klass(); }
207 bool oopDesc::is_typeArray() const { return klass()->is_typeArray_klass(); }
208
209 void* oopDesc::field_addr(int offset) const { return reinterpret_cast<void*>(cast_from_oop<intptr_t>(as_oop()) + offset); }
210
211 template <class T>
212 T* oopDesc::obj_field_addr(int offset) const { return (T*) field_addr(offset); }
213
214 template <typename T>
215 size_t oopDesc::field_offset(T* p) const { return pointer_delta((void*)p, (void*)this, 1); }
216
217 template <DecoratorSet decorators>
218 inline oop oopDesc::obj_field_access(int offset) const { return HeapAccess<decorators>::oop_load_at(as_oop(), offset); }
219 inline oop oopDesc::obj_field(int offset) const { return HeapAccess<>::oop_load_at(as_oop(), offset); }
220
221 inline void oopDesc::obj_field_put(int offset, oop value) { HeapAccess<>::oop_store_at(as_oop(), offset, value); }
222
223 inline jbyte oopDesc::byte_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
224 inline void oopDesc::byte_field_put(int offset, jbyte value) { HeapAccess<>::store_at(as_oop(), offset, value); }
225
226 inline jchar oopDesc::char_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
227 inline void oopDesc::char_field_put(int offset, jchar value) { HeapAccess<>::store_at(as_oop(), offset, value); }
228
229 inline jboolean oopDesc::bool_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
230 inline void oopDesc::bool_field_put(int offset, jboolean value) { HeapAccess<>::store_at(as_oop(), offset, jboolean(value & 1)); }
231 inline jboolean oopDesc::bool_field_volatile(int offset) const { return HeapAccess<MO_SEQ_CST>::load_at(as_oop(), offset); }
232 inline void oopDesc::bool_field_put_volatile(int offset, jboolean value) { HeapAccess<MO_SEQ_CST>::store_at(as_oop(), offset, jboolean(value & 1)); }
233 inline jshort oopDesc::short_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
234 inline void oopDesc::short_field_put(int offset, jshort value) { HeapAccess<>::store_at(as_oop(), offset, value); }
235
236 inline jint oopDesc::int_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
237 inline jint oopDesc::int_field_raw(int offset) const { return RawAccess<>::load_at(as_oop(), offset); }
238 inline void oopDesc::int_field_put(int offset, jint value) { HeapAccess<>::store_at(as_oop(), offset, value); }
239
240 inline jlong oopDesc::long_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
241 inline void oopDesc::long_field_put(int offset, jlong value) { HeapAccess<>::store_at(as_oop(), offset, value); }
242
243 inline jfloat oopDesc::float_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
244 inline void oopDesc::float_field_put(int offset, jfloat value) { HeapAccess<>::store_at(as_oop(), offset, value); }
245
246 inline jdouble oopDesc::double_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
247 inline void oopDesc::double_field_put(int offset, jdouble value) { HeapAccess<>::store_at(as_oop(), offset, value); }
248
249 bool oopDesc::is_locked() const {
250 return mark().is_locked();
251 }
252
253 bool oopDesc::is_unlocked() const {
254 return mark().is_unlocked();
255 }
256
257 bool oopDesc::has_bias_pattern() const {
258 return mark().has_bias_pattern();
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 verify_forwardee(p);
276 markWord m = markWord::encode_pointer_as_mark(p);
277 assert(m.decode_pointer() == p, "encoding must be reversable");
278 set_mark(m);
279 }
280
281 // Used by parallel scavengers
282 bool oopDesc::cas_forward_to(oop p, markWord compare, atomic_memory_order order) {
283 verify_forwardee(p);
284 markWord m = markWord::encode_pointer_as_mark(p);
285 assert(m.decode_pointer() == p, "encoding must be reversable");
286 return cas_set_mark(m, compare, order) == compare;
287 }
288
289 oop oopDesc::forward_to_atomic(oop p, markWord compare, atomic_memory_order order) {
290 verify_forwardee(p);
291 markWord m = markWord::encode_pointer_as_mark(p);
292 assert(m.decode_pointer() == p, "encoding must be reversable");
293 markWord old_mark = cas_set_mark(m, compare, order);
294 if (old_mark == compare) {
295 return NULL;
296 } else {
297 return cast_to_oop(old_mark.decode_pointer());
298 }
299 }
300
301 // Note that the forwardee is not the same thing as the displaced_mark.
302 // The forwardee is used when copying during scavenge and mark-sweep.
303 // It does need to clear the low two locking- and GC-related bits.
304 oop oopDesc::forwardee() const {
305 return cast_to_oop(mark().decode_pointer());
306 }
307
308 // The following method needs to be MT safe.
309 uint oopDesc::age() const {
310 assert(!is_forwarded(), "Attempt to read age from forwarded mark");
311 if (has_displaced_mark()) {
312 return displaced_mark().age();
313 } else {
314 return mark().age();
315 }
316 }
317
318 void oopDesc::incr_age() {
319 assert(!is_forwarded(), "Attempt to increment age of forwarded mark");
320 if (has_displaced_mark()) {
321 set_displaced_mark(displaced_mark().incr_age());
322 } else {
323 set_mark(mark().incr_age());
324 }
325 }
326
327 template <typename OopClosureType>
328 void oopDesc::oop_iterate(OopClosureType* cl) {
329 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass());
330 }
331
332 template <typename OopClosureType>
333 void oopDesc::oop_iterate(OopClosureType* cl, MemRegion mr) {
334 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass(), mr);
335 }
336
337 template <typename OopClosureType>
338 int oopDesc::oop_iterate_size(OopClosureType* cl) {
339 Klass* k = klass();
340 int size = size_given_klass(k);
341 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k);
342 return size;
343 }
344
345 template <typename OopClosureType>
346 int oopDesc::oop_iterate_size(OopClosureType* cl, MemRegion mr) {
347 Klass* k = klass();
348 int size = size_given_klass(k);
349 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k, mr);
350 return size;
351 }
352
353 template <typename OopClosureType>
354 void oopDesc::oop_iterate_backwards(OopClosureType* cl) {
355 oop_iterate_backwards(cl, klass());
356 }
357
358 template <typename OopClosureType>
359 void oopDesc::oop_iterate_backwards(OopClosureType* cl, Klass* k) {
360 assert(k == klass(), "wrong klass");
361 OopIteratorClosureDispatch::oop_oop_iterate_backwards(cl, this, k);
362 }
363
364 bool oopDesc::is_instanceof_or_null(oop obj, Klass* klass) {
365 return obj == NULL || obj->klass()->is_subtype_of(klass);
366 }
367
368 intptr_t oopDesc::identity_hash() {
369 // Fast case; if the object is unlocked and the hash value is set, no locking is needed
370 // Note: The mark must be read into local variable to avoid concurrent updates.
371 markWord mrk = mark();
372 if (mrk.is_unlocked() && !mrk.has_no_hash()) {
373 return mrk.hash();
374 } else if (mrk.is_marked()) {
375 return mrk.hash();
376 } else {
377 return slow_identity_hash();
378 }
379 }
380
381 bool oopDesc::has_displaced_mark() const {
382 return mark().has_displaced_mark_helper();
383 }
384
385 markWord oopDesc::displaced_mark() const {
386 return mark().displaced_mark_helper();
387 }
388
389 void oopDesc::set_displaced_mark(markWord m) {
390 mark().set_displaced_mark_helper(m);
391 }
392
393 bool oopDesc::mark_must_be_preserved() const {
394 return mark_must_be_preserved(mark());
395 }
396
397 bool oopDesc::mark_must_be_preserved(markWord m) const {
398 return m.must_be_preserved(this);
399 }
400
401 bool oopDesc::mark_must_be_preserved_for_promotion_failure(markWord m) const {
402 return m.must_be_preserved_for_promotion_failure(this);
403 }
404
405 #endif // SHARE_OOPS_OOP_INLINE_HPP