1 /*
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  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
  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  *
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 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
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 24 
 25 #ifndef SHARE_OOPS_OOP_INLINE_HPP
 26 #define SHARE_OOPS_OOP_INLINE_HPP
 27 
 28 #include "oops/oop.hpp"
 29 
 30 #include "memory/universe.hpp"
 31 #include "oops/access.inline.hpp"
 32 #include "oops/arrayKlass.hpp"
 33 #include "oops/arrayOop.hpp"
 34 #include "oops/compressedOops.inline.hpp"
 35 #include "oops/markWord.hpp"
 36 #include "oops/oopsHierarchy.hpp"
 37 #include "runtime/atomic.hpp"
 38 #include "runtime/globals.hpp"
 39 #include "utilities/align.hpp"
 40 #include "utilities/debug.hpp"
 41 #include "utilities/macros.hpp"
 42 #include "utilities/globalDefinitions.hpp"
 43 
 44 // Implementation of all inlined member functions defined in oop.hpp
 45 // We need a separate file to avoid circular references
 46 
 47 markWord oopDesc::mark() const {
 48   return Atomic::load(&_mark);
 49 }
 50 
 51 markWord oopDesc::mark_acquire() const {
 52   return Atomic::load_acquire(&_mark);
 53 }
 54 
 55 markWord* oopDesc::mark_addr() const {
 56   return (markWord*) &_mark;
 57 }
 58 
 59 void oopDesc::set_mark(markWord m) {
 60   Atomic::store(&_mark, m);
 61 }
 62 
 63 void oopDesc::set_mark(HeapWord* mem, markWord m) {
 64   *(markWord*)(((char*)mem) + mark_offset_in_bytes()) = m;
 65 }
 66 
 67 void oopDesc::release_set_mark(markWord m) {
 68   Atomic::release_store(&_mark, m);
 69 }
 70 
 71 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark) {
 72   return Atomic::cmpxchg(&_mark, old_mark, new_mark);
 73 }
 74 
 75 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark, atomic_memory_order order) {
 76   return Atomic::cmpxchg(&_mark, old_mark, new_mark, order);
 77 }
 78 
 79 void oopDesc::init_mark() {
 80   set_mark(markWord::prototype());
 81 }
 82 
 83 Klass* oopDesc::klass() const {
 84   if (UseCompressedClassPointers) {
 85     return CompressedKlassPointers::decode_not_null(_metadata._compressed_klass);
 86   } else {
 87     return _metadata._klass;
 88   }
 89 }
 90 
 91 Klass* oopDesc::klass_or_null() const {
 92   if (UseCompressedClassPointers) {
 93     return CompressedKlassPointers::decode(_metadata._compressed_klass);
 94   } else {
 95     return _metadata._klass;
 96   }
 97 }
 98 
 99 Klass* oopDesc::klass_or_null_acquire() const {
100   if (UseCompressedClassPointers) {
101     narrowKlass nklass = Atomic::load_acquire(&_metadata._compressed_klass);
102     return CompressedKlassPointers::decode(nklass);
103   } else {
104     return Atomic::load_acquire(&_metadata._klass);
105   }
106 }
107 
108 void oopDesc::set_klass(Klass* k) {
109   assert(Universe::is_bootstrapping() || (k != NULL && k->is_klass()), "incorrect Klass");
110   if (UseCompressedClassPointers) {
111     _metadata._compressed_klass = CompressedKlassPointers::encode_not_null(k);
112   } else {
113     _metadata._klass = k;
114   }
115 }
116 
117 void oopDesc::release_set_klass(HeapWord* mem, Klass* k) {
118   assert(Universe::is_bootstrapping() || (k != NULL && k->is_klass()), "incorrect Klass");
119   char* raw_mem = ((char*)mem + klass_offset_in_bytes());
120   if (UseCompressedClassPointers) {
121     Atomic::release_store((narrowKlass*)raw_mem,
122                           CompressedKlassPointers::encode_not_null(k));
123   } else {
124     Atomic::release_store((Klass**)raw_mem, k);
125   }
126 }
127 
128 void oopDesc::set_klass_gap(HeapWord* mem, int v) {
129   if (UseCompressedClassPointers) {
130     *(int*)(((char*)mem) + klass_gap_offset_in_bytes()) = v;
131   }
132 }
133 
134 bool oopDesc::is_a(Klass* k) const {
135   return klass()->is_subtype_of(k);
136 }
137 
138 size_t oopDesc::size()  {
139   return size_given_klass(klass());
140 }
141 
142 size_t oopDesc::size_given_klass(Klass* klass)  {
143   int lh = klass->layout_helper();
144   size_t s;
145 
146   // lh is now a value computed at class initialization that may hint
147   // at the size.  For instances, this is positive and equal to the
148   // size.  For arrays, this is negative and provides log2 of the
149   // array element size.  For other oops, it is zero and thus requires
150   // a virtual call.
151   //
152   // We go to all this trouble because the size computation is at the
153   // heart of phase 2 of mark-compaction, and called for every object,
154   // alive or dead.  So the speed here is equal in importance to the
155   // speed of allocation.
156 
157   if (lh > Klass::_lh_neutral_value) {
158     if (!Klass::layout_helper_needs_slow_path(lh)) {
159       s = lh >> LogHeapWordSize;  // deliver size scaled by wordSize
160     } else {
161       s = klass->oop_size(this);
162     }
163   } else if (lh <= Klass::_lh_neutral_value) {
164     // The most common case is instances; fall through if so.
165     if (lh < Klass::_lh_neutral_value) {
166       // Second most common case is arrays.  We have to fetch the
167       // length of the array, shift (multiply) it appropriately,
168       // up to wordSize, add the header, and align to object size.
169       size_t size_in_bytes;
170       size_t array_length = (size_t) ((arrayOop)this)->length();
171       size_in_bytes = array_length << Klass::layout_helper_log2_element_size(lh);
172       size_in_bytes += Klass::layout_helper_header_size(lh);
173 
174       // This code could be simplified, but by keeping array_header_in_bytes
175       // in units of bytes and doing it this way we can round up just once,
176       // skipping the intermediate round to HeapWordSize.
177       s = align_up(size_in_bytes, MinObjAlignmentInBytes) / HeapWordSize;
178 
179       // UseParallelGC and UseG1GC can change the length field
180       // of an "old copy" of an object array in the young gen so it indicates
181       // the grey portion of an already copied array. This will cause the first
182       // disjunct below to fail if the two comparands are computed across such
183       // a concurrent change.
184       assert((s == klass->oop_size(this)) ||
185              (Universe::is_gc_active() && is_objArray() && is_forwarded() && (get_UseParallelGC() || get_UseG1GC())),
186              "wrong array object size");
187     } else {
188       // Must be zero, so bite the bullet and take the virtual call.
189       s = klass->oop_size(this);
190     }
191   }
192 
193   assert(s > 0, "Oop size must be greater than zero, not " SIZE_FORMAT, s);
194   assert(is_object_aligned(s), "Oop size is not properly aligned: " SIZE_FORMAT, s);
195   return s;
196 }
197 
198 bool oopDesc::is_instance()  const { return klass()->is_instance_klass();  }
199 bool oopDesc::is_array()     const { return klass()->is_array_klass();     }
200 bool oopDesc::is_objArray()  const { return klass()->is_objArray_klass();  }
201 bool oopDesc::is_typeArray() const { return klass()->is_typeArray_klass(); }
202 
203 template<typename T>
204 T*       oopDesc::field_addr(int offset)     const { return reinterpret_cast<T*>(cast_from_oop<intptr_t>(as_oop()) + offset); }
205 
206 template <typename T>
207 size_t   oopDesc::field_offset(T* p) const { return pointer_delta((void*)p, (void*)this, 1); }
208 
209 template <DecoratorSet decorators>
210 inline oop  oopDesc::obj_field_access(int offset) const             { return HeapAccess<decorators>::oop_load_at(as_oop(), offset); }
211 inline oop  oopDesc::obj_field(int offset) const                    { return HeapAccess<>::oop_load_at(as_oop(), offset);  }
212 
213 inline void oopDesc::obj_field_put(int offset, oop value)           { HeapAccess<>::oop_store_at(as_oop(), offset, value); }
214 
215 inline jbyte oopDesc::byte_field(int offset) const                  { return *field_addr<jbyte>(offset);  }
216 inline void  oopDesc::byte_field_put(int offset, jbyte value)       { *field_addr<jbyte>(offset) = value; }
217 
218 inline jchar oopDesc::char_field(int offset) const                  { return *field_addr<jchar>(offset);  }
219 inline void  oopDesc::char_field_put(int offset, jchar value)       { *field_addr<jchar>(offset) = value; }
220 
221 inline jboolean oopDesc::bool_field(int offset) const               { return *field_addr<jboolean>(offset); }
222 inline void     oopDesc::bool_field_put(int offset, jboolean value) { *field_addr<jboolean>(offset) = jboolean(value & 1); }
223 inline jboolean oopDesc::bool_field_volatile(int offset) const      { return RawAccess<MO_SEQ_CST>::load(field_addr<jboolean>(offset)); }
224 inline void     oopDesc::bool_field_put_volatile(int offset, jboolean value) { RawAccess<MO_SEQ_CST>::store(field_addr<jboolean>(offset), jboolean(value & 1)); }
225 inline jshort oopDesc::short_field(int offset) const                { return *field_addr<jshort>(offset);   }
226 inline void   oopDesc::short_field_put(int offset, jshort value)    { *field_addr<jshort>(offset) = value;  }
227 
228 inline jint oopDesc::int_field(int offset) const                    { return *field_addr<jint>(offset);     }
229 inline void oopDesc::int_field_put(int offset, jint value)          { *field_addr<jint>(offset) = value;    }
230 
231 inline jlong oopDesc::long_field(int offset) const                  { return *field_addr<jlong>(offset);    }
232 inline void  oopDesc::long_field_put(int offset, jlong value)       { *field_addr<jlong>(offset) = value;   }
233 
234 inline jfloat oopDesc::float_field(int offset) const                { return *field_addr<jfloat>(offset);   }
235 inline void   oopDesc::float_field_put(int offset, jfloat value)    { *field_addr<jfloat>(offset) = value;  }
236 
237 inline jdouble oopDesc::double_field(int offset) const              { return *field_addr<jdouble>(offset);  }
238 inline void    oopDesc::double_field_put(int offset, jdouble value) { *field_addr<jdouble>(offset) = value; }
239 
240 bool oopDesc::is_locked() const {
241   return mark().is_locked();
242 }
243 
244 bool oopDesc::is_unlocked() const {
245   return mark().is_unlocked();
246 }
247 
248 // Used only for markSweep, scavenging
249 bool oopDesc::is_gc_marked() const {
250   return mark().is_marked();
251 }
252 
253 // Used by scavengers
254 bool oopDesc::is_forwarded() const {
255   // The extra heap check is needed since the obj might be locked, in which case the
256   // mark would point to a stack location and have the sentinel bit cleared
257   return mark().is_marked();
258 }
259 
260 // Used by scavengers
261 void oopDesc::forward_to(oop p) {
262   verify_forwardee(p);
263   markWord m = markWord::encode_pointer_as_mark(p);
264   assert(m.decode_pointer() == p, "encoding must be reversable");
265   set_mark(m);
266 }
267 
268 oop oopDesc::forward_to_atomic(oop p, markWord compare, atomic_memory_order order) {
269   verify_forwardee(p);
270   markWord m = markWord::encode_pointer_as_mark(p);
271   assert(m.decode_pointer() == p, "encoding must be reversable");
272   markWord old_mark = cas_set_mark(m, compare, order);
273   if (old_mark == compare) {
274     return NULL;
275   } else {
276     return cast_to_oop(old_mark.decode_pointer());
277   }
278 }
279 
280 // Note that the forwardee is not the same thing as the displaced_mark.
281 // The forwardee is used when copying during scavenge and mark-sweep.
282 // It does need to clear the low two locking- and GC-related bits.
283 oop oopDesc::forwardee() const {
284   assert(is_forwarded(), "only decode when actually forwarded");
285   return cast_to_oop(mark().decode_pointer());
286 }
287 
288 // The following method needs to be MT safe.
289 uint oopDesc::age() const {
290   assert(!mark().is_marked(), "Attempt to read age from forwarded mark");
291   if (has_displaced_mark()) {
292     return displaced_mark().age();
293   } else {
294     return mark().age();
295   }
296 }
297 
298 void oopDesc::incr_age() {
299   assert(!mark().is_marked(), "Attempt to increment age of forwarded mark");
300   if (has_displaced_mark()) {
301     set_displaced_mark(displaced_mark().incr_age());
302   } else {
303     set_mark(mark().incr_age());
304   }
305 }
306 
307 template <typename OopClosureType>
308 void oopDesc::oop_iterate(OopClosureType* cl) {
309   OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass());
310 }
311 
312 template <typename OopClosureType>
313 void oopDesc::oop_iterate(OopClosureType* cl, MemRegion mr) {
314   OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass(), mr);
315 }
316 
317 template <typename OopClosureType>
318 size_t oopDesc::oop_iterate_size(OopClosureType* cl) {
319   Klass* k = klass();
320   size_t size = size_given_klass(k);
321   OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k);
322   return size;
323 }
324 
325 template <typename OopClosureType>
326 size_t oopDesc::oop_iterate_size(OopClosureType* cl, MemRegion mr) {
327   Klass* k = klass();
328   size_t size = size_given_klass(k);
329   OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k, mr);
330   return size;
331 }
332 
333 template <typename OopClosureType>
334 void oopDesc::oop_iterate_backwards(OopClosureType* cl) {
335   oop_iterate_backwards(cl, klass());
336 }
337 
338 template <typename OopClosureType>
339 void oopDesc::oop_iterate_backwards(OopClosureType* cl, Klass* k) {
340   assert(k == klass(), "wrong klass");
341   OopIteratorClosureDispatch::oop_oop_iterate_backwards(cl, this, k);
342 }
343 
344 bool oopDesc::is_instanceof_or_null(oop obj, Klass* klass) {
345   return obj == NULL || obj->klass()->is_subtype_of(klass);
346 }
347 
348 intptr_t oopDesc::identity_hash() {
349   // Fast case; if the object is unlocked and the hash value is set, no locking is needed
350   // Note: The mark must be read into local variable to avoid concurrent updates.
351   markWord mrk = mark();
352   if (mrk.is_unlocked() && !mrk.has_no_hash()) {
353     return mrk.hash();
354   } else if (mrk.is_marked()) {
355     return mrk.hash();
356   } else {
357     return slow_identity_hash();
358   }
359 }
360 
361 bool oopDesc::has_displaced_mark() const {
362   return mark().has_displaced_mark_helper();
363 }
364 
365 markWord oopDesc::displaced_mark() const {
366   return mark().displaced_mark_helper();
367 }
368 
369 void oopDesc::set_displaced_mark(markWord m) {
370   mark().set_displaced_mark_helper(m);
371 }
372 
373 bool oopDesc::mark_must_be_preserved() const {
374   return mark_must_be_preserved(mark());
375 }
376 
377 bool oopDesc::mark_must_be_preserved(markWord m) const {
378   return m.must_be_preserved(this);
379 }
380 
381 #endif // SHARE_OOPS_OOP_INLINE_HPP