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