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  *
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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(Klass::default_prototype_header(klass()));
 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 bool oopDesc::is_inline_type() const { return mark().is_inline_type(); }
204 #ifdef _LP64
205 bool oopDesc::is_flatArray() const {
206   markWord mrk = mark();
207   return (mrk.is_unlocked()) ? mrk.is_flat_array() : klass()->is_flatArray_klass();
208 }
209 bool oopDesc::is_null_free_array() const {
210   markWord mrk = mark();
211   return (mrk.is_unlocked()) ? mrk.is_null_free_array() : klass()->is_null_free_array_klass();
212 }
213 #else
214 bool oopDesc::is_flatArray()       const { return klass()->is_flatArray_klass(); }
215 bool oopDesc::is_null_free_array() const { return klass()->is_null_free_array_klass(); }
216 #endif
217 
218 template<typename T>
219 T*       oopDesc::field_addr(int offset)     const { return reinterpret_cast<T*>(cast_from_oop<intptr_t>(as_oop()) + offset); }
220 
221 template <typename T>
222 size_t   oopDesc::field_offset(T* p) const { return pointer_delta((void*)p, (void*)this, 1); }
223 
224 template <DecoratorSet decorators>
225 inline oop  oopDesc::obj_field_access(int offset) const             { return HeapAccess<decorators>::oop_load_at(as_oop(), offset); }
226 inline oop  oopDesc::obj_field(int offset) const                    { return HeapAccess<>::oop_load_at(as_oop(), offset);  }
227 
228 inline void oopDesc::obj_field_put(int offset, oop value)           { HeapAccess<>::oop_store_at(as_oop(), offset, value); }
229 
230 inline jbyte oopDesc::byte_field(int offset) const                  { return *field_addr<jbyte>(offset);  }
231 inline void  oopDesc::byte_field_put(int offset, jbyte value)       { *field_addr<jbyte>(offset) = value; }
232 
233 inline jchar oopDesc::char_field(int offset) const                  { return *field_addr<jchar>(offset);  }
234 inline void  oopDesc::char_field_put(int offset, jchar value)       { *field_addr<jchar>(offset) = value; }
235 
236 inline jboolean oopDesc::bool_field(int offset) const               { return *field_addr<jboolean>(offset); }
237 inline void     oopDesc::bool_field_put(int offset, jboolean value) { *field_addr<jboolean>(offset) = jboolean(value & 1); }
238 inline jboolean oopDesc::bool_field_volatile(int offset) const      { return RawAccess<MO_SEQ_CST>::load(field_addr<jboolean>(offset)); }
239 inline void     oopDesc::bool_field_put_volatile(int offset, jboolean value) { RawAccess<MO_SEQ_CST>::store(field_addr<jboolean>(offset), jboolean(value & 1)); }
240 inline jshort oopDesc::short_field(int offset) const                { return *field_addr<jshort>(offset);   }
241 inline void   oopDesc::short_field_put(int offset, jshort value)    { *field_addr<jshort>(offset) = value;  }
242 
243 inline jint oopDesc::int_field(int offset) const                    { return *field_addr<jint>(offset);     }
244 inline void oopDesc::int_field_put(int offset, jint value)          { *field_addr<jint>(offset) = value;    }
245 
246 inline jlong oopDesc::long_field(int offset) const                  { return *field_addr<jlong>(offset);    }
247 inline void  oopDesc::long_field_put(int offset, jlong value)       { *field_addr<jlong>(offset) = value;   }
248 
249 inline jfloat oopDesc::float_field(int offset) const                { return *field_addr<jfloat>(offset);   }
250 inline void   oopDesc::float_field_put(int offset, jfloat value)    { *field_addr<jfloat>(offset) = value;  }
251 
252 inline jdouble oopDesc::double_field(int offset) const              { return *field_addr<jdouble>(offset);  }
253 inline void    oopDesc::double_field_put(int offset, jdouble value) { *field_addr<jdouble>(offset) = value; }
254 
255 bool oopDesc::is_locked() const {
256   return mark().is_locked();
257 }
258 
259 bool oopDesc::is_unlocked() const {
260   return mark().is_unlocked();
261 }
262 
263 // Used only for markSweep, scavenging
264 bool oopDesc::is_gc_marked() const {
265   return mark().is_marked();
266 }
267 
268 // Used by scavengers
269 bool oopDesc::is_forwarded() const {
270   // The extra heap check is needed since the obj might be locked, in which case the
271   // mark would point to a stack location and have the sentinel bit cleared
272   return mark().is_marked();
273 }
274 
275 // Used by scavengers
276 void oopDesc::forward_to(oop p) {
277   verify_forwardee(p);
278   markWord m = markWord::encode_pointer_as_mark(p);
279   assert(m.decode_pointer() == p, "encoding must be reversable");
280   set_mark(m);
281 }
282 
283 oop oopDesc::forward_to_atomic(oop p, markWord compare, atomic_memory_order order) {
284   verify_forwardee(p);
285   markWord m = markWord::encode_pointer_as_mark(p);
286   assert(m.decode_pointer() == p, "encoding must be reversable");
287   markWord old_mark = cas_set_mark(m, compare, order);
288   if (old_mark == compare) {
289     return NULL;
290   } else {
291     return cast_to_oop(old_mark.decode_pointer());
292   }
293 }
294 
295 // Note that the forwardee is not the same thing as the displaced_mark.
296 // The forwardee is used when copying during scavenge and mark-sweep.
297 // It does need to clear the low two locking- and GC-related bits.
298 oop oopDesc::forwardee() const {
299   assert(is_forwarded(), "only decode when actually forwarded");
300   return cast_to_oop(mark().decode_pointer());
301 }
302 
303 // The following method needs to be MT safe.
304 uint oopDesc::age() const {
305   assert(!mark().is_marked(), "Attempt to read age from forwarded mark");
306   if (has_displaced_mark()) {
307     return displaced_mark().age();
308   } else {
309     return mark().age();
310   }
311 }
312 
313 void oopDesc::incr_age() {
314   assert(!mark().is_marked(), "Attempt to increment age of forwarded mark");
315   if (has_displaced_mark()) {
316     set_displaced_mark(displaced_mark().incr_age());
317   } else {
318     set_mark(mark().incr_age());
319   }
320 }
321 
322 template <typename OopClosureType>
323 void oopDesc::oop_iterate(OopClosureType* cl) {
324   OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass());
325 }
326 
327 template <typename OopClosureType>
328 void oopDesc::oop_iterate(OopClosureType* cl, MemRegion mr) {
329   OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass(), mr);
330 }
331 
332 template <typename OopClosureType>
333 size_t oopDesc::oop_iterate_size(OopClosureType* cl) {
334   Klass* k = klass();
335   size_t size = size_given_klass(k);
336   OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k);
337   return size;
338 }
339 
340 template <typename OopClosureType>
341 size_t oopDesc::oop_iterate_size(OopClosureType* cl, MemRegion mr) {
342   Klass* k = klass();
343   size_t size = size_given_klass(k);
344   OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k, mr);
345   return size;
346 }
347 
348 template <typename OopClosureType>
349 void oopDesc::oop_iterate_backwards(OopClosureType* cl) {
350   oop_iterate_backwards(cl, klass());
351 }
352 
353 template <typename OopClosureType>
354 void oopDesc::oop_iterate_backwards(OopClosureType* cl, Klass* k) {
355   assert(k == klass(), "wrong klass");
356   OopIteratorClosureDispatch::oop_oop_iterate_backwards(cl, this, k);
357 }
358 
359 bool oopDesc::is_instanceof_or_null(oop obj, Klass* klass) {
360   return obj == NULL || obj->klass()->is_subtype_of(klass);
361 }
362 
363 intptr_t oopDesc::identity_hash() {
364   // Fast case; if the object is unlocked and the hash value is set, no locking is needed
365   // Note: The mark must be read into local variable to avoid concurrent updates.
366   markWord mrk = mark();
367   if (mrk.is_unlocked() && !mrk.has_no_hash()) {
368     return mrk.hash();
369   } else if (mrk.is_marked()) {
370     return mrk.hash();
371   } else {
372     return slow_identity_hash();
373   }
374 }
375 
376 bool oopDesc::has_displaced_mark() const {
377   return mark().has_displaced_mark_helper();
378 }
379 
380 markWord oopDesc::displaced_mark() const {
381   return mark().displaced_mark_helper();
382 }
383 
384 void oopDesc::set_displaced_mark(markWord m) {
385   mark().set_displaced_mark_helper(m);
386 }
387 
388 bool oopDesc::mark_must_be_preserved() const {
389   return mark_must_be_preserved(mark());
390 }
391 
392 bool oopDesc::mark_must_be_preserved(markWord m) const {
393   return m.must_be_preserved(this);
394 }
395 
396 #endif // SHARE_OOPS_OOP_INLINE_HPP