1 /*
2 * Copyright (c) 1997, 2014, 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_implementation/shared/ageTable.hpp"
29 #include "memory/barrierSet.inline.hpp"
30 #include "memory/cardTableModRefBS.hpp"
31 #include "memory/genCollectedHeap.hpp"
32 #include "memory/generation.hpp"
33 #include "memory/specialized_oop_closures.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.inline.hpp"
40 #include "runtime/orderAccess.inline.hpp"
41 #include "runtime/os.hpp"
42 #include "utilities/macros.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 inline void oopDesc::release_set_mark(markOop m) {
48 OrderAccess::release_store_ptr(&_mark, m);
49 }
50
51 inline markOop oopDesc::cas_set_mark(markOop new_mark, markOop old_mark) {
52 return (markOop) Atomic::cmpxchg_ptr(new_mark, &_mark, old_mark);
53 }
54
55 inline Klass* oopDesc::klass() const {
56 if (UseCompressedClassPointers) {
57 return Klass::decode_klass_not_null(_metadata._compressed_klass);
58 } else {
59 return _metadata._klass;
60 }
61 }
62
63 inline Klass* oopDesc::klass_or_null() const volatile {
64 // can be NULL in CMS
65 if (UseCompressedClassPointers) {
66 return Klass::decode_klass(_metadata._compressed_klass);
67 } else {
68 return _metadata._klass;
69 }
70 }
71
72 inline int oopDesc::klass_gap_offset_in_bytes() {
73 assert(UseCompressedClassPointers, "only applicable to compressed klass pointers");
74 return oopDesc::klass_offset_in_bytes() + sizeof(narrowKlass);
75 }
76
77 inline Klass** oopDesc::klass_addr() {
78 // Only used internally and with CMS and will not work with
79 // UseCompressedOops
80 assert(!UseCompressedClassPointers, "only supported with uncompressed klass pointers");
81 return (Klass**) &_metadata._klass;
82 }
83
84 inline narrowKlass* oopDesc::compressed_klass_addr() {
85 assert(UseCompressedClassPointers, "only called by compressed klass pointers");
86 return &_metadata._compressed_klass;
87 }
88
89 inline void oopDesc::set_klass(Klass* k) {
90 // since klasses are promoted no store check is needed
91 assert(Universe::is_bootstrapping() || k != NULL, "must be a real Klass*");
92 assert(Universe::is_bootstrapping() || k->is_klass(), "not a Klass*");
93 if (UseCompressedClassPointers) {
94 *compressed_klass_addr() = Klass::encode_klass_not_null(k);
95 } else {
96 *klass_addr() = k;
97 }
98 }
99
100 inline int oopDesc::klass_gap() const {
101 return *(int*)(((intptr_t)this) + klass_gap_offset_in_bytes());
102 }
103
104 inline void oopDesc::set_klass_gap(int v) {
105 if (UseCompressedClassPointers) {
106 *(int*)(((intptr_t)this) + klass_gap_offset_in_bytes()) = v;
107 }
108 }
109
110 inline void oopDesc::set_klass_to_list_ptr(oop k) {
111 // This is only to be used during GC, for from-space objects, so no
112 // barrier is needed.
113 if (UseCompressedClassPointers) {
114 _metadata._compressed_klass = (narrowKlass)encode_heap_oop(k); // may be null (parnew overflow handling)
115 } else {
116 _metadata._klass = (Klass*)(address)k;
117 }
118 }
119
120 inline oop oopDesc::list_ptr_from_klass() {
121 // This is only to be used during GC, for from-space objects.
122 if (UseCompressedClassPointers) {
123 return decode_heap_oop((narrowOop)_metadata._compressed_klass);
124 } else {
125 // Special case for GC
126 return (oop)(address)_metadata._klass;
127 }
128 }
129
130 inline void oopDesc::init_mark() { set_mark(markOopDesc::prototype_for_object(this)); }
131
132 inline bool oopDesc::is_a(Klass* k) const { return klass()->is_subtype_of(k); }
133
134 inline bool oopDesc::is_instance() const { return klass()->oop_is_instance(); }
135 inline bool oopDesc::is_instanceClassLoader() const { return klass()->oop_is_instanceClassLoader(); }
136 inline bool oopDesc::is_instanceMirror() const { return klass()->oop_is_instanceMirror(); }
137 inline bool oopDesc::is_instanceRef() const { return klass()->oop_is_instanceRef(); }
138 inline bool oopDesc::is_array() const { return klass()->oop_is_array(); }
139 inline bool oopDesc::is_objArray() const { return klass()->oop_is_objArray(); }
140 inline bool oopDesc::is_typeArray() const { return klass()->oop_is_typeArray(); }
141
142 inline void* oopDesc::field_base(int offset) const { return (void*)&((char*)this)[offset]; }
143
144 template <class T> inline T* oopDesc::obj_field_addr(int offset) const { return (T*)field_base(offset); }
145 inline Metadata** oopDesc::metadata_field_addr(int offset) const { return (Metadata**)field_base(offset); }
146 inline jbyte* oopDesc::byte_field_addr(int offset) const { return (jbyte*) field_base(offset); }
147 inline jchar* oopDesc::char_field_addr(int offset) const { return (jchar*) field_base(offset); }
148 inline jboolean* oopDesc::bool_field_addr(int offset) const { return (jboolean*)field_base(offset); }
149 inline jint* oopDesc::int_field_addr(int offset) const { return (jint*) field_base(offset); }
150 inline jshort* oopDesc::short_field_addr(int offset) const { return (jshort*) field_base(offset); }
151 inline jlong* oopDesc::long_field_addr(int offset) const { return (jlong*) field_base(offset); }
152 inline jfloat* oopDesc::float_field_addr(int offset) const { return (jfloat*) field_base(offset); }
153 inline jdouble* oopDesc::double_field_addr(int offset) const { return (jdouble*) field_base(offset); }
154 inline address* oopDesc::address_field_addr(int offset) const { return (address*) field_base(offset); }
155
156
157 // Functions for getting and setting oops within instance objects.
158 // If the oops are compressed, the type passed to these overloaded functions
159 // is narrowOop. All functions are overloaded so they can be called by
160 // template functions without conditionals (the compiler instantiates via
161 // the right type and inlines the appopriate code).
162
163 inline bool oopDesc::is_null(oop obj) { return obj == NULL; }
164 inline bool oopDesc::is_null(narrowOop obj) { return obj == 0; }
165
166 // Algorithm for encoding and decoding oops from 64 bit pointers to 32 bit
167 // offset from the heap base. Saving the check for null can save instructions
168 // in inner GC loops so these are separated.
169
170 inline bool check_obj_alignment(oop obj) {
171 return cast_from_oop<intptr_t>(obj) % MinObjAlignmentInBytes == 0;
172 }
173
174 inline narrowOop oopDesc::encode_heap_oop_not_null(oop v) {
175 assert(!is_null(v), "oop value can never be zero");
176 assert(check_obj_alignment(v), "Address not aligned");
177 assert(Universe::heap()->is_in_reserved(v), "Address not in heap");
178 address base = Universe::narrow_oop_base();
179 int shift = Universe::narrow_oop_shift();
180 uint64_t pd = (uint64_t)(pointer_delta((void*)v, (void*)base, 1));
181 assert(OopEncodingHeapMax > pd, "change encoding max if new encoding");
182 uint64_t result = pd >> shift;
183 assert((result & CONST64(0xffffffff00000000)) == 0, "narrow oop overflow");
184 assert(decode_heap_oop(result) == v, "reversibility");
185 return (narrowOop)result;
186 }
187
188 inline narrowOop oopDesc::encode_heap_oop(oop v) {
189 return (is_null(v)) ? (narrowOop)0 : encode_heap_oop_not_null(v);
190 }
191
192 inline oop oopDesc::decode_heap_oop_not_null(narrowOop v) {
193 assert(!is_null(v), "narrow oop value can never be zero");
194 address base = Universe::narrow_oop_base();
195 int shift = Universe::narrow_oop_shift();
196 oop result = (oop)(void*)((uintptr_t)base + ((uintptr_t)v << shift));
197 assert(check_obj_alignment(result), err_msg("address not aligned: " INTPTR_FORMAT, p2i((void*) result)));
198 return result;
199 }
200
201 inline oop oopDesc::decode_heap_oop(narrowOop v) {
202 return is_null(v) ? (oop)NULL : decode_heap_oop_not_null(v);
203 }
204
205 inline oop oopDesc::decode_heap_oop_not_null(oop v) { return v; }
206 inline oop oopDesc::decode_heap_oop(oop v) { return v; }
207
208 // Load an oop out of the Java heap as is without decoding.
209 // Called by GC to check for null before decoding.
210 inline oop oopDesc::load_heap_oop(oop* p) { return *p; }
211 inline narrowOop oopDesc::load_heap_oop(narrowOop* p) { return *p; }
212
213 // Load and decode an oop out of the Java heap into a wide oop.
214 inline oop oopDesc::load_decode_heap_oop_not_null(oop* p) { return *p; }
215 inline oop oopDesc::load_decode_heap_oop_not_null(narrowOop* p) {
216 return decode_heap_oop_not_null(*p);
217 }
218
219 // Load and decode an oop out of the heap accepting null
220 inline oop oopDesc::load_decode_heap_oop(oop* p) { return *p; }
221 inline oop oopDesc::load_decode_heap_oop(narrowOop* p) {
222 return decode_heap_oop(*p);
223 }
224
225 // Store already encoded heap oop into the heap.
226 inline void oopDesc::store_heap_oop(oop* p, oop v) { *p = v; }
227 inline void oopDesc::store_heap_oop(narrowOop* p, narrowOop v) { *p = v; }
228
229 // Encode and store a heap oop.
230 inline void oopDesc::encode_store_heap_oop_not_null(narrowOop* p, oop v) {
231 *p = encode_heap_oop_not_null(v);
232 }
233 inline void oopDesc::encode_store_heap_oop_not_null(oop* p, oop v) { *p = v; }
234
235 // Encode and store a heap oop allowing for null.
236 inline void oopDesc::encode_store_heap_oop(narrowOop* p, oop v) {
237 *p = encode_heap_oop(v);
238 }
239 inline void oopDesc::encode_store_heap_oop(oop* p, oop v) { *p = v; }
240
241 // Store heap oop as is for volatile fields.
242 inline void oopDesc::release_store_heap_oop(volatile oop* p, oop v) {
243 OrderAccess::release_store_ptr(p, v);
244 }
245 inline void oopDesc::release_store_heap_oop(volatile narrowOop* p,
246 narrowOop v) {
247 OrderAccess::release_store(p, v);
248 }
249
250 inline void oopDesc::release_encode_store_heap_oop_not_null(
251 volatile narrowOop* p, oop v) {
252 // heap oop is not pointer sized.
253 OrderAccess::release_store(p, encode_heap_oop_not_null(v));
254 }
255
256 inline void oopDesc::release_encode_store_heap_oop_not_null(
257 volatile oop* p, oop v) {
258 OrderAccess::release_store_ptr(p, v);
259 }
260
261 inline void oopDesc::release_encode_store_heap_oop(volatile oop* p,
262 oop v) {
263 OrderAccess::release_store_ptr(p, v);
264 }
265 inline void oopDesc::release_encode_store_heap_oop(
266 volatile narrowOop* p, oop v) {
267 OrderAccess::release_store(p, encode_heap_oop(v));
268 }
269
270
271 // These functions are only used to exchange oop fields in instances,
272 // not headers.
273 inline oop oopDesc::atomic_exchange_oop(oop exchange_value, volatile HeapWord *dest) {
274 if (UseCompressedOops) {
275 // encode exchange value from oop to T
276 narrowOop val = encode_heap_oop(exchange_value);
277 narrowOop old = (narrowOop)Atomic::xchg(val, (narrowOop*)dest);
278 // decode old from T to oop
279 return decode_heap_oop(old);
280 } else {
281 return (oop)Atomic::xchg_ptr(exchange_value, (oop*)dest);
282 }
283 }
284
285 // In order to put or get a field out of an instance, must first check
286 // if the field has been compressed and uncompress it.
287 inline oop oopDesc::obj_field(int offset) const {
288 return UseCompressedOops ?
289 load_decode_heap_oop(obj_field_addr<narrowOop>(offset)) :
290 load_decode_heap_oop(obj_field_addr<oop>(offset));
291 }
292 inline volatile oop oopDesc::obj_field_volatile(int offset) const {
293 volatile oop value = obj_field(offset);
294 OrderAccess::acquire();
295 return value;
296 }
297 inline void oopDesc::obj_field_put(int offset, oop value) {
298 UseCompressedOops ? oop_store(obj_field_addr<narrowOop>(offset), value) :
299 oop_store(obj_field_addr<oop>(offset), value);
300 }
301
302 inline Metadata* oopDesc::metadata_field(int offset) const {
303 return *metadata_field_addr(offset);
304 }
305
306 inline void oopDesc::metadata_field_put(int offset, Metadata* value) {
307 *metadata_field_addr(offset) = value;
308 }
309
310 inline void oopDesc::obj_field_put_raw(int offset, oop value) {
311 UseCompressedOops ?
312 encode_store_heap_oop(obj_field_addr<narrowOop>(offset), value) :
313 encode_store_heap_oop(obj_field_addr<oop>(offset), value);
314 }
315 inline void oopDesc::obj_field_put_volatile(int offset, oop value) {
316 OrderAccess::release();
317 obj_field_put(offset, value);
318 OrderAccess::fence();
319 }
320
321 inline jbyte oopDesc::byte_field(int offset) const { return (jbyte) *byte_field_addr(offset); }
322 inline void oopDesc::byte_field_put(int offset, jbyte contents) { *byte_field_addr(offset) = (jint) contents; }
323
324 inline jboolean oopDesc::bool_field(int offset) const { return (jboolean) *bool_field_addr(offset); }
325 inline void oopDesc::bool_field_put(int offset, jboolean contents) { *bool_field_addr(offset) = (jint) contents; }
326
327 inline jchar oopDesc::char_field(int offset) const { return (jchar) *char_field_addr(offset); }
328 inline void oopDesc::char_field_put(int offset, jchar contents) { *char_field_addr(offset) = (jint) contents; }
329
330 inline jint oopDesc::int_field(int offset) const { return *int_field_addr(offset); }
331 inline void oopDesc::int_field_put(int offset, jint contents) { *int_field_addr(offset) = contents; }
332
333 inline jshort oopDesc::short_field(int offset) const { return (jshort) *short_field_addr(offset); }
334 inline void oopDesc::short_field_put(int offset, jshort contents) { *short_field_addr(offset) = (jint) contents;}
335
336 inline jlong oopDesc::long_field(int offset) const { return *long_field_addr(offset); }
337 inline void oopDesc::long_field_put(int offset, jlong contents) { *long_field_addr(offset) = contents; }
338
339 inline jfloat oopDesc::float_field(int offset) const { return *float_field_addr(offset); }
340 inline void oopDesc::float_field_put(int offset, jfloat contents) { *float_field_addr(offset) = contents; }
341
342 inline jdouble oopDesc::double_field(int offset) const { return *double_field_addr(offset); }
343 inline void oopDesc::double_field_put(int offset, jdouble contents) { *double_field_addr(offset) = contents; }
344
345 inline address oopDesc::address_field(int offset) const { return *address_field_addr(offset); }
346 inline void oopDesc::address_field_put(int offset, address contents) { *address_field_addr(offset) = contents; }
347
348 inline oop oopDesc::obj_field_acquire(int offset) const {
349 return UseCompressedOops ?
350 decode_heap_oop((narrowOop)
351 OrderAccess::load_acquire(obj_field_addr<narrowOop>(offset)))
352 : decode_heap_oop((oop)
353 OrderAccess::load_ptr_acquire(obj_field_addr<oop>(offset)));
354 }
355 inline void oopDesc::release_obj_field_put(int offset, oop value) {
356 UseCompressedOops ?
357 oop_store((volatile narrowOop*)obj_field_addr<narrowOop>(offset), value) :
358 oop_store((volatile oop*) obj_field_addr<oop>(offset), value);
359 }
360
361 inline jbyte oopDesc::byte_field_acquire(int offset) const { return OrderAccess::load_acquire(byte_field_addr(offset)); }
362 inline void oopDesc::release_byte_field_put(int offset, jbyte contents) { OrderAccess::release_store(byte_field_addr(offset), contents); }
363
364 inline jboolean oopDesc::bool_field_acquire(int offset) const { return OrderAccess::load_acquire(bool_field_addr(offset)); }
365 inline void oopDesc::release_bool_field_put(int offset, jboolean contents) { OrderAccess::release_store(bool_field_addr(offset), contents); }
366
367 inline jchar oopDesc::char_field_acquire(int offset) const { return OrderAccess::load_acquire(char_field_addr(offset)); }
368 inline void oopDesc::release_char_field_put(int offset, jchar contents) { OrderAccess::release_store(char_field_addr(offset), contents); }
369
370 inline jint oopDesc::int_field_acquire(int offset) const { return OrderAccess::load_acquire(int_field_addr(offset)); }
371 inline void oopDesc::release_int_field_put(int offset, jint contents) { OrderAccess::release_store(int_field_addr(offset), contents); }
372
373 inline jshort oopDesc::short_field_acquire(int offset) const { return (jshort)OrderAccess::load_acquire(short_field_addr(offset)); }
374 inline void oopDesc::release_short_field_put(int offset, jshort contents) { OrderAccess::release_store(short_field_addr(offset), contents); }
375
376 inline jlong oopDesc::long_field_acquire(int offset) const { return OrderAccess::load_acquire(long_field_addr(offset)); }
377 inline void oopDesc::release_long_field_put(int offset, jlong contents) { OrderAccess::release_store(long_field_addr(offset), contents); }
378
379 inline jfloat oopDesc::float_field_acquire(int offset) const { return OrderAccess::load_acquire(float_field_addr(offset)); }
380 inline void oopDesc::release_float_field_put(int offset, jfloat contents) { OrderAccess::release_store(float_field_addr(offset), contents); }
381
382 inline jdouble oopDesc::double_field_acquire(int offset) const { return OrderAccess::load_acquire(double_field_addr(offset)); }
383 inline void oopDesc::release_double_field_put(int offset, jdouble contents) { OrderAccess::release_store(double_field_addr(offset), contents); }
384
385 inline address oopDesc::address_field_acquire(int offset) const { return (address) OrderAccess::load_ptr_acquire(address_field_addr(offset)); }
386 inline void oopDesc::release_address_field_put(int offset, address contents) { OrderAccess::release_store_ptr(address_field_addr(offset), contents); }
387
388 inline int oopDesc::size_given_klass(Klass* klass) {
389 int lh = klass->layout_helper();
390 int s;
391
392 // lh is now a value computed at class initialization that may hint
393 // at the size. For instances, this is positive and equal to the
394 // size. For arrays, this is negative and provides log2 of the
395 // array element size. For other oops, it is zero and thus requires
396 // a virtual call.
397 //
398 // We go to all this trouble because the size computation is at the
399 // heart of phase 2 of mark-compaction, and called for every object,
400 // alive or dead. So the speed here is equal in importance to the
401 // speed of allocation.
402
403 if (lh > Klass::_lh_neutral_value) {
404 if (!Klass::layout_helper_needs_slow_path(lh)) {
405 s = lh >> LogHeapWordSize; // deliver size scaled by wordSize
406 } else {
407 s = klass->oop_size(this);
408 }
409 } else if (lh <= Klass::_lh_neutral_value) {
410 // The most common case is instances; fall through if so.
411 if (lh < Klass::_lh_neutral_value) {
412 // Second most common case is arrays. We have to fetch the
413 // length of the array, shift (multiply) it appropriately,
414 // up to wordSize, add the header, and align to object size.
415 size_t size_in_bytes;
416 #ifdef _M_IA64
417 // The Windows Itanium Aug 2002 SDK hoists this load above
418 // the check for s < 0. An oop at the end of the heap will
419 // cause an access violation if this load is performed on a non
420 // array oop. Making the reference volatile prohibits this.
421 // (%%% please explain by what magic the length is actually fetched!)
422 volatile int *array_length;
423 array_length = (volatile int *)( (intptr_t)this +
424 arrayOopDesc::length_offset_in_bytes() );
425 assert(array_length > 0, "Integer arithmetic problem somewhere");
426 // Put into size_t to avoid overflow.
427 size_in_bytes = (size_t) array_length;
428 size_in_bytes = size_in_bytes << Klass::layout_helper_log2_element_size(lh);
429 #else
430 size_t array_length = (size_t) ((arrayOop)this)->length();
431 size_in_bytes = array_length << Klass::layout_helper_log2_element_size(lh);
432 #endif
433 size_in_bytes += Klass::layout_helper_header_size(lh);
434
435 // This code could be simplified, but by keeping array_header_in_bytes
436 // in units of bytes and doing it this way we can round up just once,
437 // skipping the intermediate round to HeapWordSize. Cast the result
438 // of round_to to size_t to guarantee unsigned division == right shift.
439 s = (int)((size_t)round_to(size_in_bytes, MinObjAlignmentInBytes) /
440 HeapWordSize);
441
442 // UseParNewGC, UseParallelGC and UseG1GC can change the length field
443 // of an "old copy" of an object array in the young gen so it indicates
444 // the grey portion of an already copied array. This will cause the first
445 // disjunct below to fail if the two comparands are computed across such
446 // a concurrent change.
447 // UseParNewGC also runs with promotion labs (which look like int
448 // filler arrays) which are subject to changing their declared size
449 // when finally retiring a PLAB; this also can cause the first disjunct
450 // to fail for another worker thread that is concurrently walking the block
451 // offset table. Both these invariant failures are benign for their
452 // current uses; we relax the assertion checking to cover these two cases below:
453 // is_objArray() && is_forwarded() // covers first scenario above
454 // || is_typeArray() // covers second scenario above
455 // If and when UseParallelGC uses the same obj array oop stealing/chunking
456 // technique, we will need to suitably modify the assertion.
457 assert((s == klass->oop_size(this)) ||
458 (Universe::heap()->is_gc_active() &&
459 ((is_typeArray() && UseParNewGC) ||
460 (is_objArray() && is_forwarded() && (UseParNewGC || UseParallelGC || UseG1GC)))),
461 "wrong array object size");
462 } else {
463 // Must be zero, so bite the bullet and take the virtual call.
464 s = klass->oop_size(this);
465 }
466 }
467
468 assert(s % MinObjAlignment == 0, "alignment check");
469 assert(s > 0, "Bad size calculated");
470 return s;
471 }
472
473
474 inline int oopDesc::size() {
475 return size_given_klass(klass());
476 }
477
478 inline void update_barrier_set(void* p, oop v, bool release = false) {
479 assert(oopDesc::bs() != NULL, "Uninitialized bs in oop!");
480 oopDesc::bs()->write_ref_field(p, v, release);
481 }
482
483 template <class T> inline void update_barrier_set_pre(T* p, oop v) {
484 oopDesc::bs()->write_ref_field_pre(p, v);
485 }
486
487 template <class T> inline void oop_store(T* p, oop v) {
488 if (always_do_update_barrier) {
489 oop_store((volatile T*)p, v);
490 } else {
491 update_barrier_set_pre(p, v);
492 oopDesc::encode_store_heap_oop(p, v);
493 // always_do_update_barrier == false =>
494 // Either we are at a safepoint (in GC) or CMS is not used. In both
495 // cases it's unnecessary to mark the card as dirty with release sematics.
496 update_barrier_set((void*)p, v, false /* release */); // cast away type
497 }
498 }
499
500 template <class T> inline void oop_store(volatile T* p, oop v) {
501 update_barrier_set_pre((T*)p, v); // cast away volatile
502 // Used by release_obj_field_put, so use release_store_ptr.
503 oopDesc::release_encode_store_heap_oop(p, v);
504 // When using CMS we must mark the card corresponding to p as dirty
505 // with release sematics to prevent that CMS sees the dirty card but
506 // not the new value v at p due to reordering of the two
507 // stores. Note that CMS has a concurrent precleaning phase, where
508 // it reads the card table while the Java threads are running.
509 update_barrier_set((void*)p, v, true /* release */); // cast away type
510 }
511
512 // Should replace *addr = oop assignments where addr type depends on UseCompressedOops
513 // (without having to remember the function name this calls).
514 inline void oop_store_raw(HeapWord* addr, oop value) {
515 if (UseCompressedOops) {
516 oopDesc::encode_store_heap_oop((narrowOop*)addr, value);
517 } else {
518 oopDesc::encode_store_heap_oop((oop*)addr, value);
519 }
520 }
521
522 inline oop oopDesc::atomic_compare_exchange_oop(oop exchange_value,
523 volatile HeapWord *dest,
524 oop compare_value,
525 bool prebarrier) {
526 if (UseCompressedOops) {
527 if (prebarrier) {
528 update_barrier_set_pre((narrowOop*)dest, exchange_value);
529 }
530 // encode exchange and compare value from oop to T
531 narrowOop val = encode_heap_oop(exchange_value);
532 narrowOop cmp = encode_heap_oop(compare_value);
533
534 narrowOop old = (narrowOop) Atomic::cmpxchg(val, (narrowOop*)dest, cmp);
535 // decode old from T to oop
536 return decode_heap_oop(old);
537 } else {
538 if (prebarrier) {
539 update_barrier_set_pre((oop*)dest, exchange_value);
540 }
541 return (oop)Atomic::cmpxchg_ptr(exchange_value, (oop*)dest, compare_value);
542 }
543 }
544
545 // Used only for markSweep, scavenging
546 inline bool oopDesc::is_gc_marked() const {
547 return mark()->is_marked();
548 }
549
550 inline bool oopDesc::is_locked() const {
551 return mark()->is_locked();
552 }
553
554 inline bool oopDesc::is_unlocked() const {
555 return mark()->is_unlocked();
556 }
557
558 inline bool oopDesc::has_bias_pattern() const {
559 return mark()->has_bias_pattern();
560 }
561
562
563 // used only for asserts
564 inline bool oopDesc::is_oop(bool ignore_mark_word) const {
565 oop obj = (oop) this;
566 if (!check_obj_alignment(obj)) return false;
567 if (!Universe::heap()->is_in_reserved(obj)) return false;
568 // obj is aligned and accessible in heap
569 if (Universe::heap()->is_in_reserved(obj->klass_or_null())) return false;
570
571 // Header verification: the mark is typically non-NULL. If we're
572 // at a safepoint, it must not be null.
573 // Outside of a safepoint, the header could be changing (for example,
574 // another thread could be inflating a lock on this object).
575 if (ignore_mark_word) {
576 return true;
577 }
578 if (mark() != NULL) {
579 return true;
580 }
581 return !SafepointSynchronize::is_at_safepoint();
582 }
583
584
585 // used only for asserts
586 inline bool oopDesc::is_oop_or_null(bool ignore_mark_word) const {
587 return this == NULL ? true : is_oop(ignore_mark_word);
588 }
589
590 #ifndef PRODUCT
591 // used only for asserts
592 inline bool oopDesc::is_unlocked_oop() const {
593 if (!Universe::heap()->is_in_reserved(this)) return false;
594 return mark()->is_unlocked();
595 }
596 #endif // PRODUCT
597
598 inline void oopDesc::follow_contents(void) {
599 assert (is_gc_marked(), "should be marked");
600 klass()->oop_follow_contents(this);
601 }
602
603 // Used by scavengers
604
605 inline bool oopDesc::is_forwarded() const {
606 // The extra heap check is needed since the obj might be locked, in which case the
607 // mark would point to a stack location and have the sentinel bit cleared
608 return mark()->is_marked();
609 }
610
611 // Used by scavengers
612 inline void oopDesc::forward_to(oop p) {
613 assert(check_obj_alignment(p),
614 "forwarding to something not aligned");
615 assert(Universe::heap()->is_in_reserved(p),
616 "forwarding to something not in heap");
617 markOop m = markOopDesc::encode_pointer_as_mark(p);
618 assert(m->decode_pointer() == p, "encoding must be reversable");
619 set_mark(m);
620 }
621
622 // Used by parallel scavengers
623 inline bool oopDesc::cas_forward_to(oop p, markOop compare) {
624 assert(check_obj_alignment(p),
625 "forwarding to something not aligned");
626 assert(Universe::heap()->is_in_reserved(p),
627 "forwarding to something not in heap");
628 markOop m = markOopDesc::encode_pointer_as_mark(p);
629 assert(m->decode_pointer() == p, "encoding must be reversable");
630 return cas_set_mark(m, compare) == compare;
631 }
632
633 // Note that the forwardee is not the same thing as the displaced_mark.
634 // The forwardee is used when copying during scavenge and mark-sweep.
635 // It does need to clear the low two locking- and GC-related bits.
636 inline oop oopDesc::forwardee() const {
637 return (oop) mark()->decode_pointer();
638 }
639
640 inline bool oopDesc::has_displaced_mark() const {
641 return mark()->has_displaced_mark_helper();
642 }
643
644 inline markOop oopDesc::displaced_mark() const {
645 return mark()->displaced_mark_helper();
646 }
647
648 inline void oopDesc::set_displaced_mark(markOop m) {
649 mark()->set_displaced_mark_helper(m);
650 }
651
652 // The following method needs to be MT safe.
653 inline uint oopDesc::age() const {
654 assert(!is_forwarded(), "Attempt to read age from forwarded mark");
655 if (has_displaced_mark()) {
656 return displaced_mark()->age();
657 } else {
658 return mark()->age();
659 }
660 }
661
662 inline void oopDesc::incr_age() {
663 assert(!is_forwarded(), "Attempt to increment age of forwarded mark");
664 if (has_displaced_mark()) {
665 set_displaced_mark(displaced_mark()->incr_age());
666 } else {
667 set_mark(mark()->incr_age());
668 }
669 }
670
671
672 inline intptr_t oopDesc::identity_hash() {
673 // Fast case; if the object is unlocked and the hash value is set, no locking is needed
674 // Note: The mark must be read into local variable to avoid concurrent updates.
675 markOop mrk = mark();
676 if (mrk->is_unlocked() && !mrk->has_no_hash()) {
677 return mrk->hash();
678 } else if (mrk->is_marked()) {
679 return mrk->hash();
680 } else {
681 return slow_identity_hash();
682 }
683 }
684
685 inline int oopDesc::adjust_pointers() {
686 debug_only(int check_size = size());
687 int s = klass()->oop_adjust_pointers(this);
688 assert(s == check_size, "should be the same");
689 return s;
690 }
691
692 template <bool nv, typename OopClosureType>
693 inline int oopDesc::oop_iterate(OopClosureType* blk) {
694 CONCRETE_KLASS_DO_AND_RETURN(klass(), oop_oop_iterate<nv>(this,blk));
695 }
696
697 template <bool nv, typename OopClosureType>
698 inline int oopDesc::oop_iterate(OopClosureType* blk, MemRegion mr) {
699 CONCRETE_KLASS_DO_AND_RETURN(klass(), oop_oop_iterate_m<nv>(this,blk,mr));
700 }
701
702 #if INCLUDE_ALL_GCS
703 template <bool nv, typename OopClosureType>
704 inline int oopDesc::oop_iterate_backwards(OopClosureType* blk) {
705 CONCRETE_KLASS_DO_AND_RETURN(klass(), oop_oop_iterate_backwards<nv>(this, blk));
706 }
707 #endif // INCLUDE_ALL_GCS
708
709 inline int oopDesc::oop_iterate_no_header(OopClosure* blk) {
710 // The NoHeaderExtendedOopClosure wraps the OopClosure and proxies all
711 // the do_oop calls, but turns off all other features in ExtendedOopClosure.
712 NoHeaderExtendedOopClosure cl(blk);
713 return oop_iterate(&cl);
714 }
715
716 inline int oopDesc::oop_iterate_no_header(OopClosure* blk, MemRegion mr) {
717 NoHeaderExtendedOopClosure cl(blk);
718 return oop_iterate(&cl, mr);
719 }
720
721 #endif // SHARE_VM_OOPS_OOP_INLINE_HPP