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