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.
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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 *
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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
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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.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 return Atomic::load(&_mark);
49 }
50
51 markWord oopDesc::mark_acquire() const {
52 return Atomic::load_acquire(&_mark);
53 }
54
55 markWord* oopDesc::mark_addr() const {
56 return (markWord*) &_mark;
57 }
58
59 void oopDesc::set_mark(markWord m) {
60 Atomic::store(&_mark, m);
61 }
62
63 void oopDesc::set_mark(HeapWord* mem, markWord m) {
64 *(markWord*)(((char*)mem) + mark_offset_in_bytes()) = m;
65 }
66
67 void oopDesc::release_set_mark(markWord m) {
68 Atomic::release_store(&_mark, m);
69 }
70
71 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark) {
72 return Atomic::cmpxchg(&_mark, old_mark, new_mark);
73 }
74
75 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark, atomic_memory_order order) {
76 return Atomic::cmpxchg(&_mark, old_mark, new_mark, order);
77 }
78
79 void oopDesc::init_mark() {
80 set_mark(markWord::prototype());
81 }
82
83 Klass* oopDesc::klass() const {
84 if (UseCompressedClassPointers) {
85 return CompressedKlassPointers::decode_not_null(_metadata._compressed_klass);
86 } else {
87 return _metadata._klass;
88 }
89 }
90
91 Klass* oopDesc::klass_or_null() const {
92 if (UseCompressedClassPointers) {
93 return CompressedKlassPointers::decode(_metadata._compressed_klass);
94 } else {
95 return _metadata._klass;
96 }
97 }
98
99 Klass* oopDesc::klass_or_null_acquire() const {
100 if (UseCompressedClassPointers) {
101 narrowKlass nklass = Atomic::load_acquire(&_metadata._compressed_klass);
102 return CompressedKlassPointers::decode(nklass);
103 } else {
104 return Atomic::load_acquire(&_metadata._klass);
105 }
106 }
107
108 void oopDesc::set_klass(Klass* k) {
109 assert(Universe::is_bootstrapping() || (k != NULL && k->is_klass()), "incorrect Klass");
110 if (UseCompressedClassPointers) {
111 _metadata._compressed_klass = CompressedKlassPointers::encode_not_null(k);
112 } else {
113 _metadata._klass = k;
114 }
115 }
116
117 void oopDesc::release_set_klass(HeapWord* mem, Klass* k) {
118 assert(Universe::is_bootstrapping() || (k != NULL && k->is_klass()), "incorrect Klass");
119 char* raw_mem = ((char*)mem + klass_offset_in_bytes());
120 if (UseCompressedClassPointers) {
121 Atomic::release_store((narrowKlass*)raw_mem,
122 CompressedKlassPointers::encode_not_null(k));
123 } else {
124 Atomic::release_store((Klass**)raw_mem, k);
125 }
126 }
127
128 void oopDesc::set_klass_gap(HeapWord* mem, int v) {
129 if (UseCompressedClassPointers) {
130 *(int*)(((char*)mem) + klass_gap_offset_in_bytes()) = v;
131 }
132 }
133
134 bool oopDesc::is_a(Klass* k) const {
135 return klass()->is_subtype_of(k);
136 }
137
138 size_t oopDesc::size() {
139 return size_given_klass(klass());
140 }
141
142 size_t oopDesc::size_given_klass(Klass* klass) {
143 int lh = klass->layout_helper();
144 size_t s;
145
146 // lh is now a value computed at class initialization that may hint
147 // at the size. For instances, this is positive and equal to the
148 // size. For arrays, this is negative and provides log2 of the
149 // array element size. For other oops, it is zero and thus requires
150 // a virtual call.
151 //
152 // We go to all this trouble because the size computation is at the
153 // heart of phase 2 of mark-compaction, and called for every object,
154 // alive or dead. So the speed here is equal in importance to the
155 // speed of allocation.
156
157 if (lh > Klass::_lh_neutral_value) {
158 if (!Klass::layout_helper_needs_slow_path(lh)) {
159 s = lh >> LogHeapWordSize; // deliver size scaled by wordSize
160 } else {
161 s = klass->oop_size(this);
162 }
163 } else if (lh <= Klass::_lh_neutral_value) {
164 // The most common case is instances; fall through if so.
165 if (lh < Klass::_lh_neutral_value) {
166 // Second most common case is arrays. We have to fetch the
167 // length of the array, shift (multiply) it appropriately,
168 // up to wordSize, add the header, and align to object size.
169 size_t size_in_bytes;
170 size_t array_length = (size_t) ((arrayOop)this)->length();
171 size_in_bytes = array_length << Klass::layout_helper_log2_element_size(lh);
172 size_in_bytes += Klass::layout_helper_header_size(lh);
173
174 // This code could be simplified, but by keeping array_header_in_bytes
175 // in units of bytes and doing it this way we can round up just once,
176 // skipping the intermediate round to HeapWordSize.
177 s = align_up(size_in_bytes, MinObjAlignmentInBytes) / HeapWordSize;
178
179 // UseParallelGC and UseG1GC can change the length field
180 // of an "old copy" of an object array in the young gen so it indicates
181 // the grey portion of an already copied array. This will cause the first
182 // disjunct below to fail if the two comparands are computed across such
183 // a concurrent change.
184 assert((s == klass->oop_size(this)) ||
185 (Universe::is_gc_active() && is_objArray() && is_forwarded() && (get_UseParallelGC() || get_UseG1GC())),
186 "wrong array object size");
187 } else {
188 // Must be zero, so bite the bullet and take the virtual call.
189 s = klass->oop_size(this);
190 }
191 }
192
193 assert(s > 0, "Oop size must be greater than zero, not " SIZE_FORMAT, s);
194 assert(is_object_aligned(s), "Oop size is not properly aligned: " SIZE_FORMAT, s);
195 return s;
196 }
197
198 bool oopDesc::is_instance() const { return klass()->is_instance_klass(); }
199 bool oopDesc::is_instanceRef() const { return klass()->is_reference_instance_klass(); }
200 bool oopDesc::is_array() const { return klass()->is_array_klass(); }
201 bool oopDesc::is_objArray() const { return klass()->is_objArray_klass(); }
202 bool oopDesc::is_typeArray() const { return klass()->is_typeArray_klass(); }
203
204 template<typename T>
205 T* oopDesc::field_addr(int offset) const { return reinterpret_cast<T*>(cast_from_oop<intptr_t>(as_oop()) + offset); }
206
207 template <typename T>
208 size_t oopDesc::field_offset(T* p) const { return pointer_delta((void*)p, (void*)this, 1); }
209
210 template <DecoratorSet decorators>
211 inline oop oopDesc::obj_field_access(int offset) const { return HeapAccess<decorators>::oop_load_at(as_oop(), offset); }
212 inline oop oopDesc::obj_field(int offset) const { return HeapAccess<>::oop_load_at(as_oop(), offset); }
213
214 inline void oopDesc::obj_field_put(int offset, oop value) { HeapAccess<>::oop_store_at(as_oop(), offset, value); }
215
216 inline jbyte oopDesc::byte_field(int offset) const { return *field_addr<jbyte>(offset); }
217 inline void oopDesc::byte_field_put(int offset, jbyte value) { *field_addr<jbyte>(offset) = value; }
218
219 inline jchar oopDesc::char_field(int offset) const { return *field_addr<jchar>(offset); }
220 inline void oopDesc::char_field_put(int offset, jchar value) { *field_addr<jchar>(offset) = value; }
221
222 inline jboolean oopDesc::bool_field(int offset) const { return *field_addr<jboolean>(offset); }
223 inline void oopDesc::bool_field_put(int offset, jboolean value) { *field_addr<jboolean>(offset) = jboolean(value & 1); }
224 inline jboolean oopDesc::bool_field_volatile(int offset) const { return RawAccess<MO_SEQ_CST>::load(field_addr<jboolean>(offset)); }
225 inline void oopDesc::bool_field_put_volatile(int offset, jboolean value) { RawAccess<MO_SEQ_CST>::store(field_addr<jboolean>(offset), jboolean(value & 1)); }
226 inline jshort oopDesc::short_field(int offset) const { return *field_addr<jshort>(offset); }
227 inline void oopDesc::short_field_put(int offset, jshort value) { *field_addr<jshort>(offset) = value; }
228
229 inline jint oopDesc::int_field(int offset) const { return *field_addr<jint>(offset); }
230 inline void oopDesc::int_field_put(int offset, jint value) { *field_addr<jint>(offset) = value; }
231
232 inline jlong oopDesc::long_field(int offset) const { return *field_addr<jlong>(offset); }
233 inline void oopDesc::long_field_put(int offset, jlong value) { *field_addr<jlong>(offset) = value; }
234
235 inline jfloat oopDesc::float_field(int offset) const { return *field_addr<jfloat>(offset); }
236 inline void oopDesc::float_field_put(int offset, jfloat value) { *field_addr<jfloat>(offset) = value; }
237
238 inline jdouble oopDesc::double_field(int offset) const { return *field_addr<jdouble>(offset); }
239 inline void oopDesc::double_field_put(int offset, jdouble value) { *field_addr<jdouble>(offset) = value; }
240
241 bool oopDesc::is_locked() const {
242 return mark().is_locked();
243 }
244
245 bool oopDesc::is_unlocked() const {
246 return mark().is_unlocked();
247 }
248
249 // Used only for markSweep, scavenging
250 bool oopDesc::is_gc_marked() const {
251 return mark().is_marked();
252 }
253
254 // Used by scavengers
255 bool oopDesc::is_forwarded() const {
256 // The extra heap check is needed since the obj might be locked, in which case the
257 // mark would point to a stack location and have the sentinel bit cleared
258 return mark().is_marked();
259 }
260
261 // Used by scavengers
262 void oopDesc::forward_to(oop p) {
263 verify_forwardee(p);
264 markWord m = markWord::encode_pointer_as_mark(p);
265 assert(m.decode_pointer() == p, "encoding must be reversible");
266 set_mark(m);
267 }
268
269 oop oopDesc::forward_to_atomic(oop p, markWord compare, atomic_memory_order order) {
270 verify_forwardee(p);
271 markWord m = markWord::encode_pointer_as_mark(p);
272 assert(m.decode_pointer() == p, "encoding must be reversible");
273 markWord old_mark = cas_set_mark(m, compare, order);
274 if (old_mark == compare) {
275 return NULL;
276 } else {
277 return cast_to_oop(old_mark.decode_pointer());
278 }
279 }
280
281 // Note that the forwardee is not the same thing as the displaced_mark.
282 // The forwardee is used when copying during scavenge and mark-sweep.
283 // It does need to clear the low two locking- and GC-related bits.
284 oop oopDesc::forwardee() const {
285 assert(is_forwarded(), "only decode when actually forwarded");
286 return cast_to_oop(mark().decode_pointer());
287 }
288
289 // The following method needs to be MT safe.
290 uint oopDesc::age() const {
291 assert(!mark().is_marked(), "Attempt to read age from forwarded mark");
292 if (has_displaced_mark()) {
293 return displaced_mark().age();
294 } else {
295 return mark().age();
296 }
297 }
298
299 void oopDesc::incr_age() {
300 assert(!mark().is_marked(), "Attempt to increment age of forwarded mark");
301 if (has_displaced_mark()) {
302 set_displaced_mark(displaced_mark().incr_age());
303 } else {
304 set_mark(mark().incr_age());
305 }
306 }
307
308 template <typename OopClosureType>
309 void oopDesc::oop_iterate(OopClosureType* cl) {
310 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass());
311 }
312
313 template <typename OopClosureType>
314 void oopDesc::oop_iterate(OopClosureType* cl, MemRegion mr) {
315 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass(), mr);
316 }
317
318 template <typename OopClosureType>
319 size_t oopDesc::oop_iterate_size(OopClosureType* cl) {
320 Klass* k = klass();
321 size_t size = size_given_klass(k);
322 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k);
323 return size;
324 }
325
326 template <typename OopClosureType>
327 size_t oopDesc::oop_iterate_size(OopClosureType* cl, MemRegion mr) {
328 Klass* k = klass();
329 size_t size = size_given_klass(k);
330 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k, mr);
331 return size;
332 }
333
334 template <typename OopClosureType>
335 void oopDesc::oop_iterate_backwards(OopClosureType* cl) {
336 oop_iterate_backwards(cl, klass());
337 }
338
339 template <typename OopClosureType>
340 void oopDesc::oop_iterate_backwards(OopClosureType* cl, Klass* k) {
341 assert(k == klass(), "wrong klass");
342 OopIteratorClosureDispatch::oop_oop_iterate_backwards(cl, this, k);
343 }
344
345 bool oopDesc::is_instanceof_or_null(oop obj, Klass* klass) {
346 return obj == NULL || obj->klass()->is_subtype_of(klass);
347 }
348
349 intptr_t oopDesc::identity_hash() {
350 // Fast case; if the object is unlocked and the hash value is set, no locking is needed
351 // Note: The mark must be read into local variable to avoid concurrent updates.
352 markWord mrk = mark();
353 if (mrk.is_unlocked() && !mrk.has_no_hash()) {
354 return mrk.hash();
355 } else if (mrk.is_marked()) {
356 return mrk.hash();
357 } else {
358 return slow_identity_hash();
359 }
360 }
361
362 bool oopDesc::has_displaced_mark() const {
363 return mark().has_displaced_mark_helper();
364 }
365
366 markWord oopDesc::displaced_mark() const {
367 return mark().displaced_mark_helper();
368 }
369
370 void oopDesc::set_displaced_mark(markWord m) {
371 mark().set_displaced_mark_helper(m);
372 }
373
374 bool oopDesc::mark_must_be_preserved() const {
375 return mark_must_be_preserved(mark());
376 }
377
378 bool oopDesc::mark_must_be_preserved(markWord m) const {
379 return m.must_be_preserved(this);
380 }
381
382 #endif // SHARE_OOPS_OOP_INLINE_HPP