1 /*
2 * Copyright (c) 1997, 2017, 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_VM_OOPS_OOP_INLINE_HPP
26 #define SHARE_VM_OOPS_OOP_INLINE_HPP
27
28 #include "gc/shared/ageTable.hpp"
29 #include "gc/shared/barrierSet.inline.hpp"
30 #include "gc/shared/cardTableModRefBS.hpp"
31 #include "gc/shared/collectedHeap.inline.hpp"
32 #include "gc/shared/genCollectedHeap.hpp"
33 #include "gc/shared/generation.hpp"
34 #include "oops/arrayKlass.hpp"
35 #include "oops/arrayOop.hpp"
36 #include "oops/klass.inline.hpp"
37 #include "oops/markOop.inline.hpp"
38 #include "oops/oop.hpp"
39 #include "runtime/atomic.hpp"
40 #include "runtime/orderAccess.inline.hpp"
41 #include "runtime/os.hpp"
42 #include "utilities/macros.hpp"
43
44 inline void update_barrier_set(void* p, oop v, bool release = false) {
45 assert(oopDesc::bs() != NULL, "Uninitialized bs in oop!");
46 oopDesc::bs()->write_ref_field(p, v, release);
47 }
48
49 template <class T> inline void update_barrier_set_pre(T* p, oop v) {
50 oopDesc::bs()->write_ref_field_pre(p, v);
51 }
52
53 template <class T> void oop_store(T* p, oop v) {
54 if (always_do_update_barrier) {
55 oop_store((volatile T*)p, v);
56 } else {
57 update_barrier_set_pre(p, v);
58 oopDesc::encode_store_heap_oop(p, v);
59 // always_do_update_barrier == false =>
60 // Either we are at a safepoint (in GC) or CMS is not used. In both
61 // cases it's unnecessary to mark the card as dirty with release sematics.
62 update_barrier_set((void*)p, v, false /* release */); // cast away type
63 }
64 }
65
66 template <class T> void oop_store(volatile T* p, oop v) {
67 update_barrier_set_pre((T*)p, v); // cast away volatile
68 // Used by release_obj_field_put, so use release_store_ptr.
69 oopDesc::release_encode_store_heap_oop(p, v);
70 // When using CMS we must mark the card corresponding to p as dirty
71 // with release sematics to prevent that CMS sees the dirty card but
72 // not the new value v at p due to reordering of the two
73 // stores. Note that CMS has a concurrent precleaning phase, where
74 // it reads the card table while the Java threads are running.
75 update_barrier_set((void*)p, v, true /* release */); // cast away type
76 }
77
78 // Should replace *addr = oop assignments where addr type depends on UseCompressedOops
79 // (without having to remember the function name this calls).
80 inline void oop_store_raw(HeapWord* addr, oop value) {
81 if (UseCompressedOops) {
82 oopDesc::encode_store_heap_oop((narrowOop*)addr, value);
83 } else {
84 oopDesc::encode_store_heap_oop((oop*)addr, value);
85 }
86 }
87
88 // Implementation of all inlined member functions defined in oop.hpp
89 // We need a separate file to avoid circular references
90
91 void oopDesc::release_set_mark(markOop m) {
92 OrderAccess::release_store_ptr(&_mark, m);
93 }
94
95 markOop oopDesc::cas_set_mark(markOop new_mark, markOop old_mark) {
96 return (markOop) Atomic::cmpxchg_ptr(new_mark, &_mark, old_mark);
97 }
98
99 void oopDesc::init_mark() {
100 set_mark(markOopDesc::prototype_for_object(this));
101 }
102
103 Klass* oopDesc::klass() const {
104 if (UseCompressedClassPointers) {
105 return Klass::decode_klass_not_null(_metadata._compressed_klass);
106 } else {
107 return _metadata._klass;
108 }
109 }
110
111 Klass* oopDesc::klass_or_null() const volatile {
112 if (UseCompressedClassPointers) {
113 return Klass::decode_klass(_metadata._compressed_klass);
114 } else {
115 return _metadata._klass;
116 }
117 }
118
119 Klass* oopDesc::klass_or_null_acquire() const volatile {
120 if (UseCompressedClassPointers) {
121 // Workaround for non-const load_acquire parameter.
122 const volatile narrowKlass* addr = &_metadata._compressed_klass;
123 volatile narrowKlass* xaddr = const_cast<volatile narrowKlass*>(addr);
124 return Klass::decode_klass(OrderAccess::load_acquire(xaddr));
125 } else {
126 return (Klass*)OrderAccess::load_ptr_acquire(&_metadata._klass);
127 }
128 }
129
130 Klass** oopDesc::klass_addr() {
131 // Only used internally and with CMS and will not work with
132 // UseCompressedOops
133 assert(!UseCompressedClassPointers, "only supported with uncompressed klass pointers");
134 return (Klass**) &_metadata._klass;
135 }
136
137 narrowKlass* oopDesc::compressed_klass_addr() {
138 assert(UseCompressedClassPointers, "only called by compressed klass pointers");
139 return &_metadata._compressed_klass;
140 }
141
142 #define CHECK_SET_KLASS(k) \
143 do { \
144 assert(Universe::is_bootstrapping() || k != NULL, "NULL Klass"); \
145 assert(Universe::is_bootstrapping() || k->is_klass(), "not a Klass"); \
146 } while (0)
147
148 void oopDesc::set_klass(Klass* k) {
149 CHECK_SET_KLASS(k);
150 if (UseCompressedClassPointers) {
151 *compressed_klass_addr() = Klass::encode_klass_not_null(k);
152 } else {
153 *klass_addr() = k;
154 }
155 }
156
157 void oopDesc::release_set_klass(Klass* k) {
158 CHECK_SET_KLASS(k);
159 if (UseCompressedClassPointers) {
160 OrderAccess::release_store(compressed_klass_addr(),
161 Klass::encode_klass_not_null(k));
162 } else {
163 OrderAccess::release_store_ptr(klass_addr(), k);
164 }
165 }
166
167 #undef CHECK_SET_KLASS
168
169 int oopDesc::klass_gap() const {
170 return *(int*)(((intptr_t)this) + klass_gap_offset_in_bytes());
171 }
172
173 void oopDesc::set_klass_gap(int v) {
174 if (UseCompressedClassPointers) {
175 *(int*)(((intptr_t)this) + klass_gap_offset_in_bytes()) = v;
176 }
177 }
178
179 void oopDesc::set_klass_to_list_ptr(oop k) {
180 // This is only to be used during GC, for from-space objects, so no
181 // barrier is needed.
182 if (UseCompressedClassPointers) {
183 _metadata._compressed_klass = (narrowKlass)encode_heap_oop(k); // may be null (parnew overflow handling)
184 } else {
185 _metadata._klass = (Klass*)(address)k;
186 }
187 }
188
189 oop oopDesc::list_ptr_from_klass() {
190 // This is only to be used during GC, for from-space objects.
191 if (UseCompressedClassPointers) {
192 return decode_heap_oop((narrowOop)_metadata._compressed_klass);
193 } else {
194 // Special case for GC
195 return (oop)(address)_metadata._klass;
196 }
197 }
198
199 bool oopDesc::is_a(Klass* k) const {
200 return klass()->is_subtype_of(k);
201 }
202
203 int oopDesc::size() {
204 return size_given_klass(klass());
205 }
206
207 int oopDesc::size_given_klass(Klass* klass) {
208 int lh = klass->layout_helper();
209 int s;
210
211 // lh is now a value computed at class initialization that may hint
212 // at the size. For instances, this is positive and equal to the
213 // size. For arrays, this is negative and provides log2 of the
214 // array element size. For other oops, it is zero and thus requires
215 // a virtual call.
216 //
217 // We go to all this trouble because the size computation is at the
218 // heart of phase 2 of mark-compaction, and called for every object,
219 // alive or dead. So the speed here is equal in importance to the
220 // speed of allocation.
221
222 if (lh > Klass::_lh_neutral_value) {
223 if (!Klass::layout_helper_needs_slow_path(lh)) {
224 s = lh >> LogHeapWordSize; // deliver size scaled by wordSize
225 } else {
226 s = klass->oop_size(this);
227 }
228 } else if (lh <= Klass::_lh_neutral_value) {
229 // The most common case is instances; fall through if so.
230 if (lh < Klass::_lh_neutral_value) {
231 // Second most common case is arrays. We have to fetch the
232 // length of the array, shift (multiply) it appropriately,
233 // up to wordSize, add the header, and align to object size.
234 size_t size_in_bytes;
235 size_t array_length = (size_t) ((arrayOop)this)->length();
236 size_in_bytes = array_length << Klass::layout_helper_log2_element_size(lh);
237 size_in_bytes += Klass::layout_helper_header_size(lh);
238
239 // This code could be simplified, but by keeping array_header_in_bytes
240 // in units of bytes and doing it this way we can round up just once,
241 // skipping the intermediate round to HeapWordSize.
242 s = (int)(align_up(size_in_bytes, MinObjAlignmentInBytes) / HeapWordSize);
243
244 // ParNew (used by CMS), UseParallelGC and UseG1GC can change the length field
245 // of an "old copy" of an object array in the young gen so it indicates
246 // the grey portion of an already copied array. This will cause the first
247 // disjunct below to fail if the two comparands are computed across such
248 // a concurrent change.
249 // ParNew also runs with promotion labs (which look like int
250 // filler arrays) which are subject to changing their declared size
251 // when finally retiring a PLAB; this also can cause the first disjunct
252 // to fail for another worker thread that is concurrently walking the block
253 // offset table. Both these invariant failures are benign for their
254 // current uses; we relax the assertion checking to cover these two cases below:
255 // is_objArray() && is_forwarded() // covers first scenario above
256 // || is_typeArray() // covers second scenario above
257 // If and when UseParallelGC uses the same obj array oop stealing/chunking
258 // technique, we will need to suitably modify the assertion.
259 assert((s == klass->oop_size(this)) ||
260 (Universe::heap()->is_gc_active() &&
261 ((is_typeArray() && UseConcMarkSweepGC) ||
262 (is_objArray() && is_forwarded() && (UseConcMarkSweepGC || UseParallelGC || UseG1GC)))),
263 "wrong array object size");
264 } else {
265 // Must be zero, so bite the bullet and take the virtual call.
266 s = klass->oop_size(this);
267 }
268 }
269
270 assert(s % MinObjAlignment == 0, "Oop size is not properly aligned: %d", s);
271 assert(s > 0, "Oop size must be greater than zero, not %d", s);
272 return s;
273 }
274
275 bool oopDesc::is_instance() const { return klass()->is_instance_klass(); }
276 bool oopDesc::is_array() const { return klass()->is_array_klass(); }
277 bool oopDesc::is_objArray() const { return klass()->is_objArray_klass(); }
278 bool oopDesc::is_typeArray() const { return klass()->is_typeArray_klass(); }
279
280 void* oopDesc::field_base(int offset) const { return (void*)&((char*)this)[offset]; }
281
282 jbyte* oopDesc::byte_field_addr(int offset) const { return (jbyte*) field_base(offset); }
283 jchar* oopDesc::char_field_addr(int offset) const { return (jchar*) field_base(offset); }
284 jboolean* oopDesc::bool_field_addr(int offset) const { return (jboolean*) field_base(offset); }
285 jint* oopDesc::int_field_addr(int offset) const { return (jint*) field_base(offset); }
286 jshort* oopDesc::short_field_addr(int offset) const { return (jshort*) field_base(offset); }
287 jlong* oopDesc::long_field_addr(int offset) const { return (jlong*) field_base(offset); }
288 jfloat* oopDesc::float_field_addr(int offset) const { return (jfloat*) field_base(offset); }
289 jdouble* oopDesc::double_field_addr(int offset) const { return (jdouble*) field_base(offset); }
290 Metadata** oopDesc::metadata_field_addr(int offset) const { return (Metadata**)field_base(offset); }
291
292 template <class T> T* oopDesc::obj_field_addr(int offset) const { return (T*) field_base(offset); }
293 address* oopDesc::address_field_addr(int offset) const { return (address*) field_base(offset); }
294
295
296 // Functions for getting and setting oops within instance objects.
297 // If the oops are compressed, the type passed to these overloaded functions
298 // is narrowOop. All functions are overloaded so they can be called by
299 // template functions without conditionals (the compiler instantiates via
300 // the right type and inlines the appopriate code).
301
302 // Algorithm for encoding and decoding oops from 64 bit pointers to 32 bit
303 // offset from the heap base. Saving the check for null can save instructions
304 // in inner GC loops so these are separated.
305
306 inline bool check_obj_alignment(oop obj) {
307 return (cast_from_oop<intptr_t>(obj) & MinObjAlignmentInBytesMask) == 0;
308 }
309
310 oop oopDesc::decode_heap_oop_not_null(narrowOop v) {
311 assert(!is_null(v), "narrow oop value can never be zero");
312 address base = Universe::narrow_oop_base();
313 int shift = Universe::narrow_oop_shift();
314 oop result = (oop)(void*)((uintptr_t)base + ((uintptr_t)v << shift));
315 assert(check_obj_alignment(result), "address not aligned: " INTPTR_FORMAT, p2i((void*) result));
316 return result;
317 }
318
319 oop oopDesc::decode_heap_oop(narrowOop v) {
320 return is_null(v) ? (oop)NULL : decode_heap_oop_not_null(v);
321 }
322
323 narrowOop oopDesc::encode_heap_oop_not_null(oop v) {
324 assert(!is_null(v), "oop value can never be zero");
325 assert(check_obj_alignment(v), "Address not aligned");
326 assert(Universe::heap()->is_in_reserved(v), "Address not in heap");
327 address base = Universe::narrow_oop_base();
328 int shift = Universe::narrow_oop_shift();
329 uint64_t pd = (uint64_t)(pointer_delta((void*)v, (void*)base, 1));
330 assert(OopEncodingHeapMax > pd, "change encoding max if new encoding");
331 uint64_t result = pd >> shift;
332 assert((result & CONST64(0xffffffff00000000)) == 0, "narrow oop overflow");
333 assert(decode_heap_oop(result) == v, "reversibility");
334 return (narrowOop)result;
335 }
336
337 narrowOop oopDesc::encode_heap_oop(oop v) {
338 return (is_null(v)) ? (narrowOop)0 : encode_heap_oop_not_null(v);
339 }
340
341 // Load and decode an oop out of the Java heap into a wide oop.
342 oop oopDesc::load_decode_heap_oop_not_null(narrowOop* p) {
343 return decode_heap_oop_not_null(*p);
344 }
345
346 // Load and decode an oop out of the heap accepting null
347 oop oopDesc::load_decode_heap_oop(narrowOop* p) {
348 return decode_heap_oop(*p);
349 }
350
351 // Encode and store a heap oop.
352 void oopDesc::encode_store_heap_oop_not_null(narrowOop* p, oop v) {
353 *p = encode_heap_oop_not_null(v);
354 }
355
356 // Encode and store a heap oop allowing for null.
357 void oopDesc::encode_store_heap_oop(narrowOop* p, oop v) {
358 *p = encode_heap_oop(v);
359 }
360
361 // Store heap oop as is for volatile fields.
362 void oopDesc::release_store_heap_oop(volatile oop* p, oop v) {
363 OrderAccess::release_store_ptr(p, v);
364 }
365 void oopDesc::release_store_heap_oop(volatile narrowOop* p, narrowOop v) {
366 OrderAccess::release_store(p, v);
367 }
368
369 void oopDesc::release_encode_store_heap_oop_not_null(volatile narrowOop* p, oop v) {
370 // heap oop is not pointer sized.
371 OrderAccess::release_store(p, encode_heap_oop_not_null(v));
372 }
373 void oopDesc::release_encode_store_heap_oop_not_null(volatile oop* p, oop v) {
374 OrderAccess::release_store_ptr(p, v);
375 }
376
377 void oopDesc::release_encode_store_heap_oop(volatile oop* p, oop v) {
378 OrderAccess::release_store_ptr(p, v);
379 }
380 void oopDesc::release_encode_store_heap_oop(volatile narrowOop* p, oop v) {
381 OrderAccess::release_store(p, encode_heap_oop(v));
382 }
383
384 // These functions are only used to exchange oop fields in instances,
385 // not headers.
386 oop oopDesc::atomic_exchange_oop(oop exchange_value, volatile HeapWord *dest) {
387 if (UseCompressedOops) {
388 // encode exchange value from oop to T
389 narrowOop val = encode_heap_oop(exchange_value);
390 narrowOop old = (narrowOop)Atomic::xchg(val, (narrowOop*)dest);
391 // decode old from T to oop
392 return decode_heap_oop(old);
393 } else {
394 return (oop)Atomic::xchg_ptr(exchange_value, (oop*)dest);
395 }
396 }
397
398 oop oopDesc::atomic_compare_exchange_oop(oop exchange_value,
399 volatile HeapWord *dest,
400 oop compare_value,
401 bool prebarrier) {
402 if (UseCompressedOops) {
403 if (prebarrier) {
404 update_barrier_set_pre((narrowOop*)dest, exchange_value);
405 }
406 // encode exchange and compare value from oop to T
407 narrowOop val = encode_heap_oop(exchange_value);
408 narrowOop cmp = encode_heap_oop(compare_value);
409
410 narrowOop old = (narrowOop) Atomic::cmpxchg(val, (narrowOop*)dest, cmp);
411 // decode old from T to oop
412 return decode_heap_oop(old);
413 } else {
414 if (prebarrier) {
415 update_barrier_set_pre((oop*)dest, exchange_value);
416 }
417 return (oop)Atomic::cmpxchg_ptr(exchange_value, (oop*)dest, compare_value);
418 }
419 }
420
421 // In order to put or get a field out of an instance, must first check
422 // if the field has been compressed and uncompress it.
423 oop oopDesc::obj_field(int offset) const {
424 return UseCompressedOops ?
425 load_decode_heap_oop(obj_field_addr<narrowOop>(offset)) :
426 load_decode_heap_oop(obj_field_addr<oop>(offset));
427 }
428
429 void oopDesc::obj_field_put(int offset, oop value) {
430 UseCompressedOops ? oop_store(obj_field_addr<narrowOop>(offset), value) :
431 oop_store(obj_field_addr<oop>(offset), value);
432 }
433
434 void oopDesc::obj_field_put_raw(int offset, oop value) {
435 UseCompressedOops ?
436 encode_store_heap_oop(obj_field_addr<narrowOop>(offset), value) :
437 encode_store_heap_oop(obj_field_addr<oop>(offset), value);
438 }
439 void oopDesc::obj_field_put_volatile(int offset, oop value) {
440 OrderAccess::release();
441 obj_field_put(offset, value);
442 OrderAccess::fence();
443 }
444
445 Metadata* oopDesc::metadata_field(int offset) const { return *metadata_field_addr(offset); }
446 void oopDesc::metadata_field_put(int offset, Metadata* value) { *metadata_field_addr(offset) = value; }
447
448 jbyte oopDesc::byte_field(int offset) const { return (jbyte) *byte_field_addr(offset); }
449 void oopDesc::byte_field_put(int offset, jbyte contents) { *byte_field_addr(offset) = (jint) contents; }
450
451 jchar oopDesc::char_field(int offset) const { return (jchar) *char_field_addr(offset); }
452 void oopDesc::char_field_put(int offset, jchar contents) { *char_field_addr(offset) = (jint) contents; }
453
454 jboolean oopDesc::bool_field(int offset) const { return (jboolean) *bool_field_addr(offset); }
455 void oopDesc::bool_field_put(int offset, jboolean contents) { *bool_field_addr(offset) = (((jint) contents) & 1); }
456
457 jint oopDesc::int_field(int offset) const { return *int_field_addr(offset); }
458 void oopDesc::int_field_put(int offset, jint contents) { *int_field_addr(offset) = contents; }
459
460 jshort oopDesc::short_field(int offset) const { return (jshort) *short_field_addr(offset); }
461 void oopDesc::short_field_put(int offset, jshort contents) { *short_field_addr(offset) = (jint) contents;}
462
463 jlong oopDesc::long_field(int offset) const { return *long_field_addr(offset); }
464 void oopDesc::long_field_put(int offset, jlong contents) { *long_field_addr(offset) = contents; }
465
466 jfloat oopDesc::float_field(int offset) const { return *float_field_addr(offset); }
467 void oopDesc::float_field_put(int offset, jfloat contents) { *float_field_addr(offset) = contents; }
468
469 jdouble oopDesc::double_field(int offset) const { return *double_field_addr(offset); }
470 void oopDesc::double_field_put(int offset, jdouble contents) { *double_field_addr(offset) = contents; }
471
472 address oopDesc::address_field(int offset) const { return *address_field_addr(offset); }
473 void oopDesc::address_field_put(int offset, address contents) { *address_field_addr(offset) = contents; }
474
475 oop oopDesc::obj_field_acquire(int offset) const {
476 return UseCompressedOops ?
477 decode_heap_oop((narrowOop)
478 OrderAccess::load_acquire(obj_field_addr<narrowOop>(offset)))
479 : decode_heap_oop((oop)
480 OrderAccess::load_ptr_acquire(obj_field_addr<oop>(offset)));
481 }
482 void oopDesc::release_obj_field_put(int offset, oop value) {
483 UseCompressedOops ?
484 oop_store((volatile narrowOop*)obj_field_addr<narrowOop>(offset), value) :
485 oop_store((volatile oop*) obj_field_addr<oop>(offset), value);
486 }
487
488 jbyte oopDesc::byte_field_acquire(int offset) const { return OrderAccess::load_acquire(byte_field_addr(offset)); }
489 void oopDesc::release_byte_field_put(int offset, jbyte contents) { OrderAccess::release_store(byte_field_addr(offset), contents); }
490
491 jchar oopDesc::char_field_acquire(int offset) const { return OrderAccess::load_acquire(char_field_addr(offset)); }
492 void oopDesc::release_char_field_put(int offset, jchar contents) { OrderAccess::release_store(char_field_addr(offset), contents); }
493
494 jboolean oopDesc::bool_field_acquire(int offset) const { return OrderAccess::load_acquire(bool_field_addr(offset)); }
495 void oopDesc::release_bool_field_put(int offset, jboolean contents) { OrderAccess::release_store(bool_field_addr(offset), (contents & 1)); }
496
497 jint oopDesc::int_field_acquire(int offset) const { return OrderAccess::load_acquire(int_field_addr(offset)); }
498 void oopDesc::release_int_field_put(int offset, jint contents) { OrderAccess::release_store(int_field_addr(offset), contents); }
499
500 jshort oopDesc::short_field_acquire(int offset) const { return (jshort)OrderAccess::load_acquire(short_field_addr(offset)); }
501 void oopDesc::release_short_field_put(int offset, jshort contents) { OrderAccess::release_store(short_field_addr(offset), contents); }
502
503 jlong oopDesc::long_field_acquire(int offset) const { return OrderAccess::load_acquire(long_field_addr(offset)); }
504 void oopDesc::release_long_field_put(int offset, jlong contents) { OrderAccess::release_store(long_field_addr(offset), contents); }
505
506 jfloat oopDesc::float_field_acquire(int offset) const { return OrderAccess::load_acquire(float_field_addr(offset)); }
507 void oopDesc::release_float_field_put(int offset, jfloat contents) { OrderAccess::release_store(float_field_addr(offset), contents); }
508
509 jdouble oopDesc::double_field_acquire(int offset) const { return OrderAccess::load_acquire(double_field_addr(offset)); }
510 void oopDesc::release_double_field_put(int offset, jdouble contents) { OrderAccess::release_store(double_field_addr(offset), contents); }
511
512 address oopDesc::address_field_acquire(int offset) const { return (address) OrderAccess::load_ptr_acquire(address_field_addr(offset)); }
513 void oopDesc::release_address_field_put(int offset, address contents) { OrderAccess::release_store_ptr(address_field_addr(offset), contents); }
514
515 bool oopDesc::is_locked() const {
516 return mark()->is_locked();
517 }
518
519 bool oopDesc::is_unlocked() const {
520 return mark()->is_unlocked();
521 }
522
523 bool oopDesc::has_bias_pattern() const {
524 return mark()->has_bias_pattern();
525 }
526
527 // used only for asserts
528 bool oopDesc::is_oop(bool ignore_mark_word) const {
529 oop obj = (oop) this;
530 if (!check_obj_alignment(obj)) return false;
531 if (!Universe::heap()->is_in_reserved(obj)) return false;
532 // obj is aligned and accessible in heap
533 if (Universe::heap()->is_in_reserved(obj->klass_or_null())) return false;
534
535 // Header verification: the mark is typically non-NULL. If we're
536 // at a safepoint, it must not be null.
537 // Outside of a safepoint, the header could be changing (for example,
538 // another thread could be inflating a lock on this object).
539 if (ignore_mark_word) {
540 return true;
541 }
542 if (mark() != NULL) {
543 return true;
544 }
545 return !SafepointSynchronize::is_at_safepoint();
546 }
547
548
549 // used only for asserts
550 bool oopDesc::is_oop_or_null(bool ignore_mark_word) const {
551 return this == NULL ? true : is_oop(ignore_mark_word);
552 }
553
554 #ifndef PRODUCT
555 // used only for asserts
556 bool oopDesc::is_unlocked_oop() const {
557 if (!Universe::heap()->is_in_reserved(this)) return false;
558 return mark()->is_unlocked();
559 }
560 #endif // PRODUCT
561
562 // Used only for markSweep, scavenging
563 bool oopDesc::is_gc_marked() const {
564 return mark()->is_marked();
565 }
566
567 bool oopDesc::is_scavengable() const {
568 return Universe::heap()->is_scavengable(this);
569 }
570
571 // Used by scavengers
572 bool oopDesc::is_forwarded() const {
573 // The extra heap check is needed since the obj might be locked, in which case the
574 // mark would point to a stack location and have the sentinel bit cleared
575 return mark()->is_marked();
576 }
577
578 // Used by scavengers
579 void oopDesc::forward_to(oop p) {
580 assert(check_obj_alignment(p),
581 "forwarding to something not aligned");
582 assert(Universe::heap()->is_in_reserved(p),
583 "forwarding to something not in heap");
584 markOop m = markOopDesc::encode_pointer_as_mark(p);
585 assert(m->decode_pointer() == p, "encoding must be reversable");
586 set_mark(m);
587 }
588
589 // Used by parallel scavengers
590 bool oopDesc::cas_forward_to(oop p, markOop compare) {
591 assert(check_obj_alignment(p),
592 "forwarding to something not aligned");
593 assert(Universe::heap()->is_in_reserved(p),
594 "forwarding to something not in heap");
595 markOop m = markOopDesc::encode_pointer_as_mark(p);
596 assert(m->decode_pointer() == p, "encoding must be reversable");
597 return cas_set_mark(m, compare) == compare;
598 }
599
600 #if INCLUDE_ALL_GCS
601 oop oopDesc::forward_to_atomic(oop p) {
602 markOop oldMark = mark();
603 markOop forwardPtrMark = markOopDesc::encode_pointer_as_mark(p);
604 markOop curMark;
605
606 assert(forwardPtrMark->decode_pointer() == p, "encoding must be reversable");
607 assert(sizeof(markOop) == sizeof(intptr_t), "CAS below requires this.");
608
609 while (!oldMark->is_marked()) {
610 curMark = (markOop)Atomic::cmpxchg_ptr(forwardPtrMark, &_mark, oldMark);
611 assert(is_forwarded(), "object should have been forwarded");
612 if (curMark == oldMark) {
613 return NULL;
614 }
615 // If the CAS was unsuccessful then curMark->is_marked()
616 // should return true as another thread has CAS'd in another
617 // forwarding pointer.
618 oldMark = curMark;
619 }
620 return forwardee();
621 }
622 #endif
623
624 // Note that the forwardee is not the same thing as the displaced_mark.
625 // The forwardee is used when copying during scavenge and mark-sweep.
626 // It does need to clear the low two locking- and GC-related bits.
627 oop oopDesc::forwardee() const {
628 return (oop) mark()->decode_pointer();
629 }
630
631 // The following method needs to be MT safe.
632 uint oopDesc::age() const {
633 assert(!is_forwarded(), "Attempt to read age from forwarded mark");
634 if (has_displaced_mark()) {
635 return displaced_mark()->age();
636 } else {
637 return mark()->age();
638 }
639 }
640
641 void oopDesc::incr_age() {
642 assert(!is_forwarded(), "Attempt to increment age of forwarded mark");
643 if (has_displaced_mark()) {
644 set_displaced_mark(displaced_mark()->incr_age());
645 } else {
646 set_mark(mark()->incr_age());
647 }
648 }
649
650 #if INCLUDE_ALL_GCS
651 void oopDesc::pc_follow_contents(ParCompactionManager* cm) {
652 klass()->oop_pc_follow_contents(this, cm);
653 }
654
655 void oopDesc::pc_update_contents(ParCompactionManager* cm) {
656 Klass* k = klass();
657 if (!k->is_typeArray_klass()) {
658 // It might contain oops beyond the header, so take the virtual call.
659 k->oop_pc_update_pointers(this, cm);
660 }
661 // Else skip it. The TypeArrayKlass in the header never needs scavenging.
662 }
663
664 void oopDesc::ps_push_contents(PSPromotionManager* pm) {
665 Klass* k = klass();
666 if (!k->is_typeArray_klass()) {
667 // It might contain oops beyond the header, so take the virtual call.
668 k->oop_ps_push_contents(this, pm);
669 }
670 // Else skip it. The TypeArrayKlass in the header never needs scavenging.
671 }
672 #endif // INCLUDE_ALL_GCS
673
674 #define OOP_ITERATE_DEFN(OopClosureType, nv_suffix) \
675 \
676 void oopDesc::oop_iterate(OopClosureType* blk) { \
677 klass()->oop_oop_iterate##nv_suffix(this, blk); \
678 } \
679 \
680 void oopDesc::oop_iterate(OopClosureType* blk, MemRegion mr) { \
681 klass()->oop_oop_iterate_bounded##nv_suffix(this, blk, mr); \
682 }
683
684 #define OOP_ITERATE_SIZE_DEFN(OopClosureType, nv_suffix) \
685 \
686 int oopDesc::oop_iterate_size(OopClosureType* blk) { \
687 Klass* k = klass(); \
688 int size = size_given_klass(k); \
689 k->oop_oop_iterate##nv_suffix(this, blk); \
690 return size; \
691 } \
692 \
693 int oopDesc::oop_iterate_size(OopClosureType* blk, MemRegion mr) { \
694 Klass* k = klass(); \
695 int size = size_given_klass(k); \
696 k->oop_oop_iterate_bounded##nv_suffix(this, blk, mr); \
697 return size; \
698 }
699
700 int oopDesc::oop_iterate_no_header(OopClosure* blk) {
701 // The NoHeaderExtendedOopClosure wraps the OopClosure and proxies all
702 // the do_oop calls, but turns off all other features in ExtendedOopClosure.
703 NoHeaderExtendedOopClosure cl(blk);
704 return oop_iterate_size(&cl);
705 }
706
707 int oopDesc::oop_iterate_no_header(OopClosure* blk, MemRegion mr) {
708 NoHeaderExtendedOopClosure cl(blk);
709 return oop_iterate_size(&cl, mr);
710 }
711
712 #if INCLUDE_ALL_GCS
713 #define OOP_ITERATE_BACKWARDS_DEFN(OopClosureType, nv_suffix) \
714 \
715 inline void oopDesc::oop_iterate_backwards(OopClosureType* blk) { \
716 klass()->oop_oop_iterate_backwards##nv_suffix(this, blk); \
717 }
718 #else
719 #define OOP_ITERATE_BACKWARDS_DEFN(OopClosureType, nv_suffix)
720 #endif // INCLUDE_ALL_GCS
721
722 #define ALL_OOPDESC_OOP_ITERATE(OopClosureType, nv_suffix) \
723 OOP_ITERATE_DEFN(OopClosureType, nv_suffix) \
724 OOP_ITERATE_SIZE_DEFN(OopClosureType, nv_suffix) \
725 OOP_ITERATE_BACKWARDS_DEFN(OopClosureType, nv_suffix)
726
727 ALL_OOP_OOP_ITERATE_CLOSURES_1(ALL_OOPDESC_OOP_ITERATE)
728 ALL_OOP_OOP_ITERATE_CLOSURES_2(ALL_OOPDESC_OOP_ITERATE)
729
730 intptr_t oopDesc::identity_hash() {
731 // Fast case; if the object is unlocked and the hash value is set, no locking is needed
732 // Note: The mark must be read into local variable to avoid concurrent updates.
733 markOop mrk = mark();
734 if (mrk->is_unlocked() && !mrk->has_no_hash()) {
735 return mrk->hash();
736 } else if (mrk->is_marked()) {
737 return mrk->hash();
738 } else {
739 return slow_identity_hash();
740 }
741 }
742
743 bool oopDesc::has_displaced_mark() const {
744 return mark()->has_displaced_mark_helper();
745 }
746
747 markOop oopDesc::displaced_mark() const {
748 return mark()->displaced_mark_helper();
749 }
750
751 void oopDesc::set_displaced_mark(markOop m) {
752 mark()->set_displaced_mark_helper(m);
753 }
754
755 #endif // SHARE_VM_OOPS_OOP_INLINE_HPP