1 /*
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  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_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/compressedKlass.inline.hpp"
 35 #include "oops/compressedOops.inline.hpp"
 36 #include "oops/instanceKlass.hpp"
 37 #include "oops/markWord.inline.hpp"
 38 #include "oops/oopsHierarchy.hpp"
 39 #include "runtime/atomic.hpp"
 40 #include "runtime/globals.hpp"
 41 #include "runtime/objectMonitor.inline.hpp"
 42 #include "runtime/safepoint.hpp"
 43 #include "runtime/synchronizer.hpp"
 44 #include "utilities/align.hpp"
 45 #include "utilities/debug.hpp"
 46 #include "utilities/macros.hpp"
 47 #include "utilities/globalDefinitions.hpp"
 48 
 49 // Implementation of all inlined member functions defined in oop.hpp
 50 // We need a separate file to avoid circular references
 51 
 52 markWord oopDesc::mark() const {
 53   return Atomic::load(&_mark);
 54 }
 55 
 56 markWord oopDesc::mark_acquire() const {
 57   return Atomic::load_acquire(&_mark);
 58 }
 59 
 60 markWord* oopDesc::mark_addr() const {
 61   return (markWord*) &_mark;
 62 }
 63 
 64 void oopDesc::set_mark(markWord m) {
 65   Atomic::store(&_mark, m);
 66 }
 67 
 68 void oopDesc::set_mark(HeapWord* mem, markWord m) {
 69   *(markWord*)(((char*)mem) + mark_offset_in_bytes()) = m;
 70 }
 71 
 72 void oopDesc::release_set_mark(markWord m) {
 73   Atomic::release_store(&_mark, m);
 74 }
 75 
 76 void oopDesc::release_set_mark(HeapWord* mem, markWord m) {
 77   Atomic::release_store((markWord*)(((char*)mem) + mark_offset_in_bytes()), m);
 78 }
 79 
 80 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark) {
 81   return Atomic::cmpxchg(&_mark, old_mark, new_mark);
 82 }
 83 
 84 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark, atomic_memory_order order) {
 85   return Atomic::cmpxchg(&_mark, old_mark, new_mark, order);
 86 }
 87 
 88 markWord oopDesc::resolve_mark() const {
 89   markWord hdr = mark();
 90   if (hdr.has_monitor()) {
 91     ObjectMonitor* monitor = hdr.monitor();
 92     return monitor->header();
 93   }
 94   return hdr;
 95 }
 96 
 97 void oopDesc::init_mark() {
 98 #ifdef _LP64
 99   markWord header = resolve_mark();
100   assert(UseCompressedClassPointers, "expect compressed klass pointers");
101   header = markWord((header.value() & markWord::klass_mask_in_place) | markWord::prototype().value());
102 #else
103   markWord header = markWord::prototype();
104 #endif
105   set_mark(header);
106 }
107 
108 Klass* oopDesc::klass() const {
109 #ifdef _LP64
110   assert(UseCompressedClassPointers, "only with compressed class pointers");
111   markWord header = resolve_mark();
112   return header.klass();
113 #else
114   return _klass;
115 #endif
116 }
117 
118 Klass* oopDesc::klass_or_null() const {
119 #ifdef _LP64
120   assert(UseCompressedClassPointers, "only with compressed class pointers");
121   markWord header = resolve_mark();
122   return header.klass_or_null();
123 #else
124   return _klass;
125 #endif
126 }
127 
128 Klass* oopDesc::klass_or_null_acquire() const {
129 #ifdef _LP64
130   assert(UseCompressedClassPointers, "only with compressed class pointers");
131   markWord header = mark_acquire();
132   if (header.has_monitor()) {
133     header = header.monitor()->header();
134   }
135   return header.klass_or_null();
136 #else
137   return Atomic::load_acquire(&_klass);
138 #endif
139 }
140 
141 #ifndef _LP64
142 void oopDesc::set_klass(Klass* k) {
143   assert(Universe::is_bootstrapping() || (k != NULL && k->is_klass()), "incorrect Klass");
144   _klass = k;
145 }
146 
147 void oopDesc::release_set_klass(HeapWord* mem, Klass* k) {
148   assert(Universe::is_bootstrapping() || (k != NULL && k->is_klass()), "incorrect Klass");
149   char* raw_mem = ((char*)mem + klass_offset_in_bytes());
150   if (UseCompressedClassPointers) {
151     Atomic::release_store((narrowKlass*)raw_mem,
152                           CompressedKlassPointers::encode_not_null(k));
153   } else {
154     Atomic::release_store((Klass**)raw_mem, k);
155   }
156 }
157 #endif
158 
159 bool oopDesc::is_a(Klass* k) const {
160   return klass()->is_subtype_of(k);
161 }
162 
163 size_t oopDesc::size()  {
164   return size_given_klass(klass());
165 }
166 
167 size_t oopDesc::size_given_klass(Klass* klass)  {
168   int lh = klass->layout_helper();
169   size_t s;
170 
171   // lh is now a value computed at class initialization that may hint
172   // at the size.  For instances, this is positive and equal to the
173   // size.  For arrays, this is negative and provides log2 of the
174   // array element size.  For other oops, it is zero and thus requires
175   // a virtual call.
176   //
177   // We go to all this trouble because the size computation is at the
178   // heart of phase 2 of mark-compaction, and called for every object,
179   // alive or dead.  So the speed here is equal in importance to the
180   // speed of allocation.
181 
182   if (lh > Klass::_lh_neutral_value) {
183     if (!Klass::layout_helper_needs_slow_path(lh)) {
184       s = lh >> LogHeapWordSize;  // deliver size scaled by wordSize
185     } else {
186       s = klass->oop_size(this);
187     }
188   } else if (lh <= Klass::_lh_neutral_value) {
189     // The most common case is instances; fall through if so.
190     if (lh < Klass::_lh_neutral_value) {
191       // Second most common case is arrays.  We have to fetch the
192       // length of the array, shift (multiply) it appropriately,
193       // up to wordSize, add the header, and align to object size.
194       size_t size_in_bytes;
195       size_t array_length = (size_t) ((arrayOop)this)->length();
196       size_in_bytes = array_length << Klass::layout_helper_log2_element_size(lh);
197       size_in_bytes += Klass::layout_helper_header_size(lh);
198 
199       // This code could be simplified, but by keeping array_header_in_bytes
200       // in units of bytes and doing it this way we can round up just once,
201       // skipping the intermediate round to HeapWordSize.
202       s = align_up(size_in_bytes, MinObjAlignmentInBytes) / HeapWordSize;
203 
204       assert(s == klass->oop_size(this) || size_might_change(), "wrong array object size");
205     } else {
206       // Must be zero, so bite the bullet and take the virtual call.
207       s = klass->oop_size(this);
208     }
209   }
210 
211   assert(s > 0, "Oop size must be greater than zero, not " SIZE_FORMAT, s);
212   assert(is_object_aligned(s), "Oop size is not properly aligned: " SIZE_FORMAT, s);
213   return s;
214 }
215 
216 bool oopDesc::is_instance()    const { return klass()->is_instance_klass();             }
217 bool oopDesc::is_instanceRef() const { return klass()->is_reference_instance_klass();   }
218 bool oopDesc::is_stackChunk()  const { return klass()->is_stack_chunk_instance_klass(); }
219 bool oopDesc::is_array()       const { return klass()->is_array_klass();                }
220 bool oopDesc::is_objArray()    const { return klass()->is_objArray_klass();             }
221 bool oopDesc::is_typeArray()   const { return klass()->is_typeArray_klass();            }
222 
223 template<typename T>
224 T*       oopDesc::field_addr(int offset)     const { return reinterpret_cast<T*>(cast_from_oop<intptr_t>(as_oop()) + offset); }
225 
226 template <typename T>
227 size_t   oopDesc::field_offset(T* p) const { return pointer_delta((void*)p, (void*)this, 1); }
228 
229 template <DecoratorSet decorators>
230 inline oop  oopDesc::obj_field_access(int offset) const             { return HeapAccess<decorators>::oop_load_at(as_oop(), offset); }
231 inline oop  oopDesc::obj_field(int offset) const                    { return HeapAccess<>::oop_load_at(as_oop(), offset);  }
232 
233 inline void oopDesc::obj_field_put(int offset, oop value)           { HeapAccess<>::oop_store_at(as_oop(), offset, value); }
234 template <DecoratorSet decorators>
235 inline void oopDesc::obj_field_put_access(int offset, oop value)    { HeapAccess<decorators>::oop_store_at(as_oop(), offset, value); }
236 
237 inline jbyte oopDesc::byte_field(int offset) const                  { return *field_addr<jbyte>(offset);  }
238 inline void  oopDesc::byte_field_put(int offset, jbyte value)       { *field_addr<jbyte>(offset) = value; }
239 
240 inline jchar oopDesc::char_field(int offset) const                  { return *field_addr<jchar>(offset);  }
241 inline void  oopDesc::char_field_put(int offset, jchar value)       { *field_addr<jchar>(offset) = value; }
242 
243 inline jboolean oopDesc::bool_field(int offset) const               { return *field_addr<jboolean>(offset); }
244 inline void     oopDesc::bool_field_put(int offset, jboolean value) { *field_addr<jboolean>(offset) = jboolean(value & 1); }
245 inline jboolean oopDesc::bool_field_volatile(int offset) const      { return RawAccess<MO_SEQ_CST>::load(field_addr<jboolean>(offset)); }
246 inline void     oopDesc::bool_field_put_volatile(int offset, jboolean value) { RawAccess<MO_SEQ_CST>::store(field_addr<jboolean>(offset), jboolean(value & 1)); }
247 inline jshort oopDesc::short_field(int offset) const                { return *field_addr<jshort>(offset);   }
248 inline void   oopDesc::short_field_put(int offset, jshort value)    { *field_addr<jshort>(offset) = value;  }
249 
250 inline jint oopDesc::int_field(int offset) const                    { return *field_addr<jint>(offset);     }
251 inline void oopDesc::int_field_put(int offset, jint value)          { *field_addr<jint>(offset) = value;    }
252 
253 inline jlong oopDesc::long_field(int offset) const                  { return *field_addr<jlong>(offset);    }
254 inline void  oopDesc::long_field_put(int offset, jlong value)       { *field_addr<jlong>(offset) = value;   }
255 
256 inline jfloat oopDesc::float_field(int offset) const                { return *field_addr<jfloat>(offset);   }
257 inline void   oopDesc::float_field_put(int offset, jfloat value)    { *field_addr<jfloat>(offset) = value;  }
258 
259 inline jdouble oopDesc::double_field(int offset) const              { return *field_addr<jdouble>(offset);  }
260 inline void    oopDesc::double_field_put(int offset, jdouble value) { *field_addr<jdouble>(offset) = value; }
261 
262 bool oopDesc::is_locked() const {
263   return mark().is_locked();
264 }
265 
266 bool oopDesc::is_unlocked() const {
267   return mark().is_unlocked();
268 }
269 
270 // Used only for markSweep, scavenging
271 bool oopDesc::is_gc_marked() const {
272   return mark().is_marked();
273 }
274 
275 // Used by scavengers
276 bool oopDesc::is_forwarded() const {
277   // The extra heap check is needed since the obj might be locked, in which case the
278   // mark would point to a stack location and have the sentinel bit cleared
279   return mark().is_marked();
280 }
281 
282 // Used by scavengers
283 void oopDesc::forward_to(oop p) {
284   verify_forwardee(p);
285   markWord m = markWord::encode_pointer_as_mark(p);
286   assert(forwardee(m) == p, "encoding must be reversable");
287   set_mark(m);
288 }
289 
290 void oopDesc::forward_to_self() {
291 #ifdef _LP64
292   verify_forwardee(this);
293   markWord m = mark();
294   // If mark is displaced, we need to preserve the Klass* from real header.
295   assert(SafepointSynchronize::is_at_safepoint(), "we can only safely fetch the displaced header at safepoint");
296   if (m.has_displaced_mark_helper()) {
297     m = m.displaced_mark_helper();
298   }
299   m = m.set_self_forwarded();
300   assert(forwardee(m) == cast_to_oop(this), "encoding must be reversable");
301   set_mark(m);
302 #else
303   forward_to(oop(this));
304 #endif
305 }
306 
307 oop oopDesc::forward_to_atomic(oop p, markWord compare, atomic_memory_order order) {
308   verify_forwardee(p);
309   markWord m = markWord::encode_pointer_as_mark(p);
310   assert(forwardee(m) == p, "encoding must be reversable");
311   markWord old_mark = cas_set_mark(m, compare, order);
312   if (old_mark == compare) {
313     return NULL;
314   } else {
315     return forwardee(old_mark);
316   }
317 }
318 
319 oop oopDesc::forward_to_self_atomic(markWord compare, atomic_memory_order order) {
320 #ifdef _LP64
321   verify_forwardee(this);
322   markWord m = compare;
323   // If mark is displaced, we need to preserve the Klass* from real header.
324   assert(SafepointSynchronize::is_at_safepoint(), "we can only safely fetch the displaced header at safepoint");
325   if (m.has_displaced_mark_helper()) {
326     m = m.displaced_mark_helper();
327   }
328   m = m.set_self_forwarded();
329   assert(forwardee(m) == cast_to_oop(this), "encoding must be reversable");
330   markWord old_mark = cas_set_mark(m, compare, order);
331   if (old_mark == compare) {
332     return NULL;
333   } else {
334     assert(old_mark.is_marked(), "must be marked here");
335     return forwardee(old_mark);
336   }
337 #else
338   return forward_to_atomic(oop(this), compare, order);
339 #endif
340 }
341 
342 // Note that the forwardee is not the same thing as the displaced_mark.
343 // The forwardee is used when copying during scavenge and mark-sweep.
344 // It does need to clear the low two locking- and GC-related bits.
345 oop oopDesc::forwardee() const {
346   return forwardee(mark());
347 }
348 
349 oop oopDesc::forwardee(markWord header) const {
350   assert(header.is_marked(), "must be forwarded");
351 #ifdef _LP64
352   if (header.self_forwarded()) {
353     return cast_to_oop(this);
354   } else
355 #endif
356   {
357     assert(header.is_marked(), "only decode when actually forwarded");
358     return cast_to_oop(header.decode_pointer());
359   }
360 }
361 
362 // The following method needs to be MT safe.
363 uint oopDesc::age() const {
364   assert(!mark().is_marked(), "Attempt to read age from forwarded mark");
365   if (has_displaced_mark()) {
366     return displaced_mark().age();
367   } else {
368     return mark().age();
369   }
370 }
371 
372 void oopDesc::incr_age() {
373   assert(!mark().is_marked(), "Attempt to increment age of forwarded mark");
374   if (has_displaced_mark()) {
375     set_displaced_mark(displaced_mark().incr_age());
376   } else {
377     set_mark(mark().incr_age());
378   }
379 }
380 
381 template <typename OopClosureType>
382 void oopDesc::oop_iterate(OopClosureType* cl) {
383   OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass());
384 }
385 
386 template <typename OopClosureType>
387 void oopDesc::oop_iterate(OopClosureType* cl, MemRegion mr) {
388   OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass(), mr);
389 }
390 
391 template <typename OopClosureType>
392 size_t oopDesc::oop_iterate_size(OopClosureType* cl) {
393   Klass* k = klass();
394   size_t size = size_given_klass(k);
395   OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k);
396   return size;
397 }
398 
399 template <typename OopClosureType>
400 size_t oopDesc::oop_iterate_size(OopClosureType* cl, MemRegion mr) {
401   Klass* k = klass();
402   size_t size = size_given_klass(k);
403   OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k, mr);
404   return size;
405 }
406 
407 template <typename OopClosureType>
408 void oopDesc::oop_iterate_backwards(OopClosureType* cl) {
409   oop_iterate_backwards(cl, klass());
410 }
411 
412 template <typename OopClosureType>
413 void oopDesc::oop_iterate_backwards(OopClosureType* cl, Klass* k) {
414   OopIteratorClosureDispatch::oop_oop_iterate_backwards(cl, this, k);
415 }
416 
417 bool oopDesc::is_instanceof_or_null(oop obj, Klass* klass) {
418   return obj == NULL || obj->klass()->is_subtype_of(klass);
419 }
420 
421 intptr_t oopDesc::identity_hash() {
422   // Fast case; if the object is unlocked and the hash value is set, no locking is needed
423   // Note: The mark must be read into local variable to avoid concurrent updates.
424   markWord mrk = mark();
425   if (mrk.is_unlocked() && !mrk.has_no_hash()) {
426     return mrk.hash();
427   } else if (mrk.is_marked()) {
428     return mrk.hash();
429   } else {
430     return slow_identity_hash();
431   }
432 }
433 
434 // This checks fast simple case of whether the oop has_no_hash,
435 // to optimize JVMTI table lookup.
436 bool oopDesc::fast_no_hash_check() {
437   markWord mrk = mark_acquire();
438   assert(!mrk.is_marked(), "should never be marked");
439   return mrk.is_unlocked() && mrk.has_no_hash();
440 }
441 
442 bool oopDesc::has_displaced_mark() const {
443   return mark().has_displaced_mark_helper();
444 }
445 
446 markWord oopDesc::displaced_mark() const {
447   return mark().displaced_mark_helper();
448 }
449 
450 void oopDesc::set_displaced_mark(markWord m) {
451   mark().set_displaced_mark_helper(m);
452 }
453 
454 bool oopDesc::mark_must_be_preserved() const {
455   return mark_must_be_preserved(mark());
456 }
457 
458 bool oopDesc::mark_must_be_preserved(markWord m) const {
459   return m.must_be_preserved(this);
460 }
461 
462 #endif // SHARE_OOPS_OOP_INLINE_HPP