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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 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.inline.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   uintptr_t v = HeapAccess<MO_RELAXED>::load_at(as_oop(), mark_offset_in_bytes());
 49   return markWord(v);
 50 }
 51 
 52 markWord* oopDesc::mark_addr() const {
 53   return (markWord*) &_mark;
 54 }
 55 
 56 void oopDesc::set_mark(markWord m) {
 57   HeapAccess<MO_RELAXED>::store_at(as_oop(), mark_offset_in_bytes(), m.value());
 58 }
 59 
 60 void oopDesc::set_mark(HeapWord* mem, markWord m) {
 61   *(markWord*)(((char*)mem) + mark_offset_in_bytes()) = m;
 62 }
 63 
 64 void oopDesc::release_set_mark(markWord m) {
 65   HeapAccess<MO_RELEASE>::store_at(as_oop(), mark_offset_in_bytes(), m.value());
 66 }
 67 
 68 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark) {
 69   uintptr_t v = HeapAccess<>::atomic_cmpxchg_at(as_oop(), mark_offset_in_bytes(), old_mark.value(), new_mark.value());
 70   return markWord(v);
 71 }
 72 
 73 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark, atomic_memory_order order) {
 74   return Atomic::cmpxchg(&_mark, old_mark, new_mark, order);
 75 }
 76 
 77 void oopDesc::init_mark() {
 78   set_mark(markWord::prototype_for_klass(klass()));
 79 }
 80 
 81 Klass* oopDesc::klass() const {
 82   if (UseCompressedClassPointers) {
 83     return CompressedKlassPointers::decode_not_null(_metadata._compressed_klass);
 84   } else {
 85     return _metadata._klass;
 86   }
 87 }
 88 
 89 Klass* oopDesc::klass_or_null() const {
 90   if (UseCompressedClassPointers) {
 91     return CompressedKlassPointers::decode(_metadata._compressed_klass);
 92   } else {
 93     return _metadata._klass;
 94   }
 95 }
 96 
 97 Klass* oopDesc::klass_or_null_acquire() const {
 98   if (UseCompressedClassPointers) {
 99     narrowKlass nklass = Atomic::load_acquire(&_metadata._compressed_klass);
100     return CompressedKlassPointers::decode(nklass);
101   } else {
102     return Atomic::load_acquire(&_metadata._klass);
103   }
104 }
105 
106 void oopDesc::set_klass(Klass* k) {
107   assert(Universe::is_bootstrapping() || (k != NULL && k->is_klass()), "incorrect Klass");
108   if (UseCompressedClassPointers) {
109     _metadata._compressed_klass = CompressedKlassPointers::encode_not_null(k);
110   } else {
111     _metadata._klass = k;
112   }
113 }
114 
115 void oopDesc::release_set_klass(HeapWord* mem, Klass* k) {
116   assert(Universe::is_bootstrapping() || (k != NULL && k->is_klass()), "incorrect Klass");
117   char* raw_mem = ((char*)mem + klass_offset_in_bytes());
118   if (UseCompressedClassPointers) {
119     Atomic::release_store((narrowKlass*)raw_mem,
120                           CompressedKlassPointers::encode_not_null(k));
121   } else {
122     Atomic::release_store((Klass**)raw_mem, k);
123   }
124 }
125 
126 int oopDesc::klass_gap() const {
127   return *(int*)(((intptr_t)this) + klass_gap_offset_in_bytes());
128 }
129 
130 void oopDesc::set_klass_gap(HeapWord* mem, int v) {
131   if (UseCompressedClassPointers) {
132     *(int*)(((char*)mem) + klass_gap_offset_in_bytes()) = v;
133   }
134 }
135 
136 void oopDesc::set_klass_gap(int v) {
137   set_klass_gap((HeapWord*)this, v);
138 }
139 
140 bool oopDesc::is_a(Klass* k) const {
141   return klass()->is_subtype_of(k);
142 }
143 
144 int oopDesc::size()  {
145   return size_given_klass(klass());
146 }
147 
148 int oopDesc::size_given_klass(Klass* klass)  {
149   int lh = klass->layout_helper();
150   int s;
151 
152   // lh is now a value computed at class initialization that may hint
153   // at the size.  For instances, this is positive and equal to the
154   // size.  For arrays, this is negative and provides log2 of the
155   // array element size.  For other oops, it is zero and thus requires
156   // a virtual call.
157   //
158   // We go to all this trouble because the size computation is at the
159   // heart of phase 2 of mark-compaction, and called for every object,
160   // alive or dead.  So the speed here is equal in importance to the
161   // speed of allocation.
162 
163   if (lh > Klass::_lh_neutral_value) {
164     if (!Klass::layout_helper_needs_slow_path(lh)) {
165       s = lh >> LogHeapWordSize;  // deliver size scaled by wordSize
166     } else {
167       s = klass->oop_size(this);
168     }
169   } else if (lh <= Klass::_lh_neutral_value) {
170     // The most common case is instances; fall through if so.
171     if (lh < Klass::_lh_neutral_value) {
172       // Second most common case is arrays.  We have to fetch the
173       // length of the array, shift (multiply) it appropriately,
174       // up to wordSize, add the header, and align to object size.
175       size_t size_in_bytes;
176       size_t array_length = (size_t) ((arrayOop)this)->length();
177       size_in_bytes = array_length << Klass::layout_helper_log2_element_size(lh);
178       size_in_bytes += Klass::layout_helper_header_size(lh);
179 
180       // This code could be simplified, but by keeping array_header_in_bytes
181       // in units of bytes and doing it this way we can round up just once,
182       // skipping the intermediate round to HeapWordSize.
183       s = (int)(align_up(size_in_bytes, MinObjAlignmentInBytes) / HeapWordSize);
184 
185       // UseParallelGC and UseG1GC can change the length field
186       // of an "old copy" of an object array in the young gen so it indicates
187       // the grey portion of an already copied array. This will cause the first
188       // disjunct below to fail if the two comparands are computed across such
189       // a concurrent change.
190       assert((s == klass->oop_size(this)) ||
191              (Universe::is_gc_active() && is_objArray() && is_forwarded() && (get_UseParallelGC() || get_UseG1GC())),
192              "wrong array object size");
193     } else {
194       // Must be zero, so bite the bullet and take the virtual call.
195       s = klass->oop_size(this);
196     }
197   }
198 
199   assert(s > 0, "Oop size must be greater than zero, not %d", s);
200   assert(is_object_aligned(s), "Oop size is not properly aligned: %d", s);
201   return s;
202 }
203 
204 bool oopDesc::is_instance()  const { return klass()->is_instance_klass();  }
205 bool oopDesc::is_array()     const { return klass()->is_array_klass();     }
206 bool oopDesc::is_objArray()  const { return klass()->is_objArray_klass();  }
207 bool oopDesc::is_typeArray() const { return klass()->is_typeArray_klass(); }
208 
209 void*    oopDesc::field_addr(int offset)     const { return reinterpret_cast<void*>(cast_from_oop<intptr_t>(as_oop()) + offset); }
210 
211 template <class T>
212 T*       oopDesc::obj_field_addr(int offset) const { return (T*) field_addr(offset); }
213 
214 template <typename T>
215 size_t   oopDesc::field_offset(T* p) const { return pointer_delta((void*)p, (void*)this, 1); }
216 
217 template <DecoratorSet decorators>
218 inline oop  oopDesc::obj_field_access(int offset) const             { return HeapAccess<decorators>::oop_load_at(as_oop(), offset); }
219 inline oop  oopDesc::obj_field(int offset) const                    { return HeapAccess<>::oop_load_at(as_oop(), offset);  }
220 
221 inline void oopDesc::obj_field_put(int offset, oop value)           { HeapAccess<>::oop_store_at(as_oop(), offset, value); }
222 
223 inline jbyte oopDesc::byte_field(int offset) const                  { return HeapAccess<>::load_at(as_oop(), offset);  }
224 inline void  oopDesc::byte_field_put(int offset, jbyte value)       { HeapAccess<>::store_at(as_oop(), offset, value); }
225 
226 inline jchar oopDesc::char_field(int offset) const                  { return HeapAccess<>::load_at(as_oop(), offset);  }
227 inline void  oopDesc::char_field_put(int offset, jchar value)       { HeapAccess<>::store_at(as_oop(), offset, value); }
228 
229 inline jboolean oopDesc::bool_field(int offset) const               { return HeapAccess<>::load_at(as_oop(), offset); }
230 inline void     oopDesc::bool_field_put(int offset, jboolean value) { HeapAccess<>::store_at(as_oop(), offset, jboolean(value & 1)); }
231 inline jboolean oopDesc::bool_field_volatile(int offset) const      { return HeapAccess<MO_SEQ_CST>::load_at(as_oop(), offset); }
232 inline void     oopDesc::bool_field_put_volatile(int offset, jboolean value) { HeapAccess<MO_SEQ_CST>::store_at(as_oop(), offset, jboolean(value & 1)); }
233 inline jshort oopDesc::short_field(int offset) const                { return HeapAccess<>::load_at(as_oop(), offset);  }
234 inline void   oopDesc::short_field_put(int offset, jshort value)    { HeapAccess<>::store_at(as_oop(), offset, value); }
235 
236 inline jint oopDesc::int_field(int offset) const                    { return HeapAccess<>::load_at(as_oop(), offset);  }
237 inline jint oopDesc::int_field_raw(int offset) const                { return RawAccess<>::load_at(as_oop(), offset);   }
238 inline void oopDesc::int_field_put(int offset, jint value)          { HeapAccess<>::store_at(as_oop(), offset, value); }
239 
240 inline jlong oopDesc::long_field(int offset) const                  { return HeapAccess<>::load_at(as_oop(), offset);  }
241 inline void  oopDesc::long_field_put(int offset, jlong value)       { HeapAccess<>::store_at(as_oop(), offset, value); }
242 
243 inline jfloat oopDesc::float_field(int offset) const                { return HeapAccess<>::load_at(as_oop(), offset);  }
244 inline void   oopDesc::float_field_put(int offset, jfloat value)    { HeapAccess<>::store_at(as_oop(), offset, value); }
245 
246 inline jdouble oopDesc::double_field(int offset) const              { return HeapAccess<>::load_at(as_oop(), offset);  }
247 inline void    oopDesc::double_field_put(int offset, jdouble value) { HeapAccess<>::store_at(as_oop(), offset, value); }
248 
249 bool oopDesc::is_locked() const {
250   return mark().is_locked();
251 }
252 
253 bool oopDesc::is_unlocked() const {
254   return mark().is_unlocked();
255 }
256 
257 bool oopDesc::has_bias_pattern() const {
258   return mark().has_bias_pattern();
259 }
260 
261 // Used only for markSweep, scavenging
262 bool oopDesc::is_gc_marked() const {
263   return mark().is_marked();
264 }
265 
266 // Used by scavengers
267 bool oopDesc::is_forwarded() const {
268   // The extra heap check is needed since the obj might be locked, in which case the
269   // mark would point to a stack location and have the sentinel bit cleared
270   return mark().is_marked();
271 }
272 
273 // Used by scavengers
274 void oopDesc::forward_to(oop p) {
275   verify_forwardee(p);
276   markWord m = markWord::encode_pointer_as_mark(p);
277   assert(m.decode_pointer() == p, "encoding must be reversable");
278   set_mark(m);
279 }
280 
281 // Used by parallel scavengers
282 bool oopDesc::cas_forward_to(oop p, markWord compare, atomic_memory_order order) {
283   verify_forwardee(p);
284   markWord m = markWord::encode_pointer_as_mark(p);
285   assert(m.decode_pointer() == p, "encoding must be reversable");
286   return cas_set_mark(m, compare, order) == compare;
287 }
288 
289 oop oopDesc::forward_to_atomic(oop p, markWord compare, atomic_memory_order order) {
290   verify_forwardee(p);
291   markWord m = markWord::encode_pointer_as_mark(p);
292   assert(m.decode_pointer() == p, "encoding must be reversable");
293   markWord old_mark = cas_set_mark(m, compare, order);
294   if (old_mark == compare) {
295     return NULL;
296   } else {
297     return cast_to_oop(old_mark.decode_pointer());
298   }
299 }
300 
301 // Note that the forwardee is not the same thing as the displaced_mark.
302 // The forwardee is used when copying during scavenge and mark-sweep.
303 // It does need to clear the low two locking- and GC-related bits.
304 oop oopDesc::forwardee() const {
305   return cast_to_oop(mark().decode_pointer());
306 }
307 
308 // The following method needs to be MT safe.
309 uint oopDesc::age() const {
310   assert(!is_forwarded(), "Attempt to read age from forwarded mark");
311   if (has_displaced_mark()) {
312     return displaced_mark().age();
313   } else {
314     return mark().age();
315   }
316 }
317 
318 void oopDesc::incr_age() {
319   assert(!is_forwarded(), "Attempt to increment age of forwarded mark");
320   if (has_displaced_mark()) {
321     set_displaced_mark(displaced_mark().incr_age());
322   } else {
323     set_mark(mark().incr_age());
324   }
325 }
326 
327 template <typename OopClosureType>
328 void oopDesc::oop_iterate(OopClosureType* cl) {
329   OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass());
330 }
331 
332 template <typename OopClosureType>
333 void oopDesc::oop_iterate(OopClosureType* cl, MemRegion mr) {
334   OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass(), mr);
335 }
336 
337 template <typename OopClosureType>
338 int oopDesc::oop_iterate_size(OopClosureType* cl) {
339   Klass* k = klass();
340   int size = size_given_klass(k);
341   OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k);
342   return size;
343 }
344 
345 template <typename OopClosureType>
346 int oopDesc::oop_iterate_size(OopClosureType* cl, MemRegion mr) {
347   Klass* k = klass();
348   int size = size_given_klass(k);
349   OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k, mr);
350   return size;
351 }
352 
353 template <typename OopClosureType>
354 void oopDesc::oop_iterate_backwards(OopClosureType* cl) {
355   oop_iterate_backwards(cl, klass());
356 }
357 
358 template <typename OopClosureType>
359 void oopDesc::oop_iterate_backwards(OopClosureType* cl, Klass* k) {
360   assert(k == klass(), "wrong klass");
361   OopIteratorClosureDispatch::oop_oop_iterate_backwards(cl, this, k);
362 }
363 
364 bool oopDesc::is_instanceof_or_null(oop obj, Klass* klass) {
365   return obj == NULL || obj->klass()->is_subtype_of(klass);
366 }
367 
368 intptr_t oopDesc::identity_hash() {
369   // Fast case; if the object is unlocked and the hash value is set, no locking is needed
370   // Note: The mark must be read into local variable to avoid concurrent updates.
371   markWord mrk = mark();
372   if (mrk.is_unlocked() && !mrk.has_no_hash()) {
373     return mrk.hash();
374   } else if (mrk.is_marked()) {
375     return mrk.hash();
376   } else {
377     return slow_identity_hash();
378   }
379 }
380 
381 bool oopDesc::has_displaced_mark() const {
382   return mark().has_displaced_mark_helper();
383 }
384 
385 markWord oopDesc::displaced_mark() const {
386   return mark().displaced_mark_helper();
387 }
388 
389 void oopDesc::set_displaced_mark(markWord m) {
390   mark().set_displaced_mark_helper(m);
391 }
392 
393 bool oopDesc::mark_must_be_preserved() const {
394   return mark_must_be_preserved(mark());
395 }
396 
397 bool oopDesc::mark_must_be_preserved(markWord m) const {
398   return m.must_be_preserved(this);
399 }
400 
401 bool oopDesc::mark_must_be_preserved_for_promotion_failure(markWord m) const {
402   return m.must_be_preserved_for_promotion_failure(this);
403 }
404 
405 #endif // SHARE_OOPS_OOP_INLINE_HPP