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