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.
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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  *
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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
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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/iterator.inline.hpp"
 31 #include "memory/universe.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.inline.hpp"
 38 #include "oops/objLayout.inline.hpp"
 39 #include "oops/oopsHierarchy.hpp"
 40 #include "runtime/arguments.hpp"
 41 #include "runtime/atomicAccess.hpp"
 42 #include "runtime/globals.hpp"
 43 #include "utilities/align.hpp"
 44 #include "utilities/debug.hpp"
 45 #include "utilities/globalDefinitions.hpp"
 46 #include "utilities/macros.hpp"
 47 
 48 // Implementation of all inlined member functions defined in oop.hpp
 49 // We need a separate file to avoid circular references
 50 
 51 void* oopDesc::base_addr() { return this; }
 52 const void* oopDesc::base_addr() const { return this; }
 53 
 54 markWord oopDesc::mark() const {
 55   return AtomicAccess::load(&_mark);
 56 }
 57 
 58 markWord oopDesc::mark_acquire() const {
 59   return AtomicAccess::load_acquire(&_mark);
 60 }
 61 
 62 void oopDesc::set_mark(markWord m) {
 63   AtomicAccess::store(&_mark, m);
 64 }
 65 
 66 void oopDesc::set_mark(HeapWord* mem, markWord m) {
 67   *(markWord*)(((char*)mem) + mark_offset_in_bytes()) = m;
 68 }
 69 
 70 void oopDesc::release_set_mark(HeapWord* mem, markWord m) {
 71   AtomicAccess::release_store((markWord*)(((char*)mem) + mark_offset_in_bytes()), m);
 72 }
 73 
 74 void oopDesc::release_set_mark(markWord m) {
 75   AtomicAccess::release_store(&_mark, m);
 76 }
 77 
 78 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark) {
 79   return AtomicAccess::cmpxchg(&_mark, old_mark, new_mark);
 80 }
 81 
 82 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark, atomic_memory_order order) {
 83   return AtomicAccess::cmpxchg(&_mark, old_mark, new_mark, order);
 84 }
 85 
 86 markWord oopDesc::prototype_mark() const {
 87   if (UseCompactObjectHeaders || Arguments::is_valhalla_enabled()) {
 88     return klass()->prototype_header();
 89   } else {
 90     return markWord::prototype();
 91   }
 92 }
 93 
 94 void oopDesc::init_mark() {
 95   set_mark(prototype_mark());
 96 }
 97 
 98 Klass* oopDesc::klass() const {
 99   switch (ObjLayout::klass_mode()) {
100     case ObjLayout::Compact:
101       return mark().klass();
102     case ObjLayout::Compressed:
103       return CompressedKlassPointers::decode_not_null(_metadata._compressed_klass);
104     default:
105       return _metadata._klass;
106   }
107 }
108 
109 Klass* oopDesc::klass_or_null() const {
110   switch (ObjLayout::klass_mode()) {
111     case ObjLayout::Compact:
112       return mark().klass_or_null();
113     case ObjLayout::Compressed:
114       return CompressedKlassPointers::decode(_metadata._compressed_klass);
115     default:
116       return _metadata._klass;
117   }
118 }
119 
120 Klass* oopDesc::klass_or_null_acquire() const {
121   switch (ObjLayout::klass_mode()) {
122     case ObjLayout::Compact:
123       return mark_acquire().klass();
124     case ObjLayout::Compressed: {
125       narrowKlass narrow_klass = AtomicAccess::load_acquire(&_metadata._compressed_klass);
126       return CompressedKlassPointers::decode(narrow_klass);
127     }
128     default:
129       return AtomicAccess::load_acquire(&_metadata._klass);
130   }
131 }
132 
133 Klass* oopDesc::klass_without_asserts() const {
134   switch (ObjLayout::klass_mode()) {
135     case ObjLayout::Compact:
136       return mark().klass_without_asserts();
137     case ObjLayout::Compressed:
138       return CompressedKlassPointers::decode_without_asserts(_metadata._compressed_klass);
139     default:
140       return _metadata._klass;
141   }
142 }
143 
144 narrowKlass oopDesc::narrow_klass() const {
145   switch (ObjLayout::klass_mode()) {
146     case ObjLayout::Compact:
147       return mark().narrow_klass();
148     case ObjLayout::Compressed:
149       return _metadata._compressed_klass;
150     default:
151       ShouldNotReachHere();
152   }
153 }
154 
155 void oopDesc::set_klass(Klass* k) {
156   assert(Universe::is_bootstrapping() || (k != nullptr && k->is_klass()), "incorrect Klass");
157   assert(!UseCompactObjectHeaders, "don't set Klass* with compact headers");
158   if (UseCompressedClassPointers) {
159     _metadata._compressed_klass = CompressedKlassPointers::encode_not_null(k);
160   } else {
161     _metadata._klass = k;
162   }
163 }
164 
165 void oopDesc::release_set_klass(HeapWord* mem, Klass* k) {
166   assert(Universe::is_bootstrapping() || (k != nullptr && k->is_klass()), "incorrect Klass");
167   assert(!UseCompactObjectHeaders, "don't set Klass* with compact headers");
168   char* raw_mem = ((char*)mem + klass_offset_in_bytes());
169   if (UseCompressedClassPointers) {
170     AtomicAccess::release_store((narrowKlass*)raw_mem,
171                           CompressedKlassPointers::encode_not_null(k));
172   } else {
173     AtomicAccess::release_store((Klass**)raw_mem, k);
174   }
175 }
176 
177 void oopDesc::set_klass_gap(HeapWord* mem, int v) {
178   assert(has_klass_gap(), "precondition");
179   *(int*)(((char*)mem) + klass_gap_offset_in_bytes()) = v;
180 }
181 
182 bool oopDesc::is_a(Klass* k) const {
183   return klass()->is_subtype_of(k);
184 }
185 
186 size_t oopDesc::size()  {
187   return size_given_klass(klass());
188 }
189 
190 size_t oopDesc::size_given_klass(Klass* klass)  {
191   int lh = klass->layout_helper();
192   size_t s;
193 
194   // lh is now a value computed at class initialization that may hint
195   // at the size.  For instances, this is positive and equal to the
196   // size.  For arrays, this is negative and provides log2 of the
197   // array element size.  For other oops, it is zero and thus requires
198   // a virtual call.
199   //
200   // We go to all this trouble because the size computation is at the
201   // heart of phase 2 of mark-compaction, and called for every object,
202   // alive or dead.  So the speed here is equal in importance to the
203   // speed of allocation.
204 
205   if (lh > Klass::_lh_neutral_value) {
206     if (!Klass::layout_helper_needs_slow_path(lh)) {
207       s = lh >> LogHeapWordSize;  // deliver size scaled by wordSize
208     } else {
209       s = klass->oop_size(this);
210     }
211   } else if (lh <= Klass::_lh_neutral_value) {
212     // The most common case is instances; fall through if so.
213     if (lh < Klass::_lh_neutral_value) {
214       // Second most common case is arrays.  We have to fetch the
215       // length of the array, shift (multiply) it appropriately,
216       // up to wordSize, add the header, and align to object size.
217       size_t size_in_bytes;
218       size_t array_length = (size_t) ((arrayOop)this)->length();
219       size_in_bytes = array_length << Klass::layout_helper_log2_element_size(lh);
220       size_in_bytes += Klass::layout_helper_header_size(lh);
221 
222       // This code could be simplified, but by keeping array_header_in_bytes
223       // in units of bytes and doing it this way we can round up just once,
224       // skipping the intermediate round to HeapWordSize.
225       s = align_up(size_in_bytes, MinObjAlignmentInBytes) / HeapWordSize;
226 
227       assert(s == klass->oop_size(this), "wrong array object size");
228     } else {
229       // Must be zero, so bite the bullet and take the virtual call.
230       s = klass->oop_size(this);
231     }
232   }
233 
234   assert(s > 0, "Oop size must be greater than zero, not %zu", s);
235   assert(is_object_aligned(s), "Oop size is not properly aligned: %zu", s);
236   return s;
237 }
238 
239 bool oopDesc::is_instance()    const { return klass()->is_instance_klass();             }
240 bool oopDesc::is_instanceRef() const { return klass()->is_reference_instance_klass();   }
241 bool oopDesc::is_stackChunk()  const { return klass()->is_stack_chunk_instance_klass(); }
242 bool oopDesc::is_array()       const { return klass()->is_array_klass();                }
243 bool oopDesc::is_objArray()    const { return klass()->is_objArray_klass();             }
244 bool oopDesc::is_refArray()    const { return klass()->is_refArray_klass();             }
245 bool oopDesc::is_typeArray()   const { return klass()->is_typeArray_klass();            }
246 bool oopDesc::is_refined_objArray() const { return klass()->is_refined_objArray_klass(); }
247 
248 bool oopDesc::is_inline_type() const { return mark().is_inline_type(); }
249 #ifdef _LP64
250 bool oopDesc::is_flatArray() const {
251   markWord mrk = mark();
252   return (mrk.is_unlocked()) ? mrk.is_flat_array() : klass()->is_flatArray_klass();
253 }
254 bool oopDesc::is_null_free_array() const {
255   markWord mrk = mark();
256   return (mrk.is_unlocked()) ? mrk.is_null_free_array() : klass()->is_null_free_array_klass();
257 }
258 #else
259 bool oopDesc::is_flatArray()       const { return klass()->is_flatArray_klass(); }
260 bool oopDesc::is_null_free_array() const { return klass()->is_null_free_array_klass(); }
261 #endif
262 
263 template<typename T>
264 T*       oopDesc::field_addr(int offset)     const { return reinterpret_cast<T*>(cast_from_oop<intptr_t>(as_oop()) + offset); }
265 
266 template <typename T>
267 size_t   oopDesc::field_offset(T* p) const { return pointer_delta((void*)p, (void*)this, 1); }
268 
269 template <DecoratorSet decorators>
270 inline oop  oopDesc::obj_field_access(int offset) const             { return HeapAccess<decorators>::oop_load_at(as_oop(), offset); }
271 inline oop  oopDesc::obj_field(int offset) const                    { return HeapAccess<>::oop_load_at(as_oop(), offset);  }
272 
273 inline void oopDesc::obj_field_put(int offset, oop value)           { HeapAccess<>::oop_store_at(as_oop(), offset, value); }
274 template <DecoratorSet decorators>
275 inline void oopDesc::obj_field_put_access(int offset, oop value)    { HeapAccess<decorators>::oop_store_at(as_oop(), offset, value); }
276 
277 inline jbyte oopDesc::byte_field(int offset) const                  { return *field_addr<jbyte>(offset);  }
278 inline void  oopDesc::byte_field_put(int offset, jbyte value)       { *field_addr<jbyte>(offset) = value; }
279 
280 inline jchar oopDesc::char_field(int offset) const                  { return *field_addr<jchar>(offset);  }
281 inline void  oopDesc::char_field_put(int offset, jchar value)       { *field_addr<jchar>(offset) = value; }
282 
283 inline jboolean oopDesc::bool_field(int offset) const               { return *field_addr<jboolean>(offset); }
284 inline void     oopDesc::bool_field_put(int offset, jboolean value) { *field_addr<jboolean>(offset) = jboolean(value & 1); }
285 inline jboolean oopDesc::bool_field_volatile(int offset) const      { return RawAccess<MO_SEQ_CST>::load(field_addr<jboolean>(offset)); }
286 inline void     oopDesc::bool_field_put_volatile(int offset, jboolean value) { RawAccess<MO_SEQ_CST>::store(field_addr<jboolean>(offset), jboolean(value & 1)); }
287 inline jshort oopDesc::short_field(int offset) const                { return *field_addr<jshort>(offset);   }
288 inline void   oopDesc::short_field_put(int offset, jshort value)    { *field_addr<jshort>(offset) = value;  }
289 
290 inline jint oopDesc::int_field(int offset) const                    { return *field_addr<jint>(offset);     }
291 inline void oopDesc::int_field_put(int offset, jint value)          { *field_addr<jint>(offset) = value;    }
292 inline jint oopDesc::int_field_relaxed(int offset) const            { return AtomicAccess::load(field_addr<jint>(offset)); }
293 inline void oopDesc::int_field_put_relaxed(int offset, jint value)  { AtomicAccess::store(field_addr<jint>(offset), value); }
294 
295 inline jlong oopDesc::long_field(int offset) const                  { return *field_addr<jlong>(offset);    }
296 inline void  oopDesc::long_field_put(int offset, jlong value)       { *field_addr<jlong>(offset) = value;   }
297 
298 inline jfloat oopDesc::float_field(int offset) const                { return *field_addr<jfloat>(offset);   }
299 inline void   oopDesc::float_field_put(int offset, jfloat value)    { *field_addr<jfloat>(offset) = value;  }
300 
301 inline jdouble oopDesc::double_field(int offset) const              { return *field_addr<jdouble>(offset);  }
302 inline void    oopDesc::double_field_put(int offset, jdouble value) { *field_addr<jdouble>(offset) = value; }
303 
304 bool oopDesc::is_locked() const {
305   return mark().is_locked();
306 }
307 
308 bool oopDesc::is_unlocked() const {
309   return mark().is_unlocked();
310 }
311 
312 bool oopDesc::is_gc_marked() const {
313   return mark().is_marked();
314 }
315 
316 // Used by scavengers
317 bool oopDesc::is_forwarded() const {
318   return mark().is_forwarded();
319 }
320 
321 bool oopDesc::is_self_forwarded() const {
322   return mark().is_self_forwarded();
323 }
324 
325 // Used by scavengers
326 void oopDesc::forward_to(oop p) {
327   assert(cast_from_oop<oopDesc*>(p) != this,
328          "must not be used for self-forwarding, use forward_to_self() instead");
329   markWord m = markWord::encode_pointer_as_mark(p);
330   assert(m.decode_pointer() == p, "encoding must be reversible");
331   set_mark(m);
332 }
333 
334 void oopDesc::forward_to_self() {
335   set_mark(mark().set_self_forwarded());
336 }
337 
338 oop oopDesc::cas_set_forwardee(markWord new_mark, markWord compare, atomic_memory_order order) {
339   markWord old_mark = cas_set_mark(new_mark, compare, order);
340   if (old_mark == compare) {
341     return nullptr;
342   } else {
343     assert(old_mark.is_forwarded(), "must be forwarded here");
344     return forwardee(old_mark);
345   }
346 }
347 
348 oop oopDesc::forward_to_atomic(oop p, markWord compare, atomic_memory_order order) {
349   assert(cast_from_oop<oopDesc*>(p) != this,
350          "must not be used for self-forwarding, use forward_to_self_atomic() instead");
351   markWord m = markWord::encode_pointer_as_mark(p);
352   assert(forwardee(m) == p, "encoding must be reversible");
353   return cas_set_forwardee(m, compare, order);
354 }
355 
356 oop oopDesc::forward_to_self_atomic(markWord old_mark, atomic_memory_order order) {
357   markWord new_mark = old_mark.set_self_forwarded();
358   assert(forwardee(new_mark) == cast_to_oop(this), "encoding must be reversible");
359   return cas_set_forwardee(new_mark, old_mark, order);
360 }
361 
362 oop oopDesc::forwardee(markWord mark) const {
363   assert(mark.is_forwarded(), "only decode when actually forwarded");
364   if (mark.is_self_forwarded()) {
365     return cast_to_oop(this);
366   } else {
367     return mark.forwardee();
368   }
369 }
370 
371 // Note that the forwardee is not the same thing as the displaced_mark.
372 // The forwardee is used when copying during scavenge and mark-sweep.
373 // It does need to clear the low two locking- and GC-related bits.
374 oop oopDesc::forwardee() const {
375   return forwardee(mark());
376 }
377 
378 void oopDesc::unset_self_forwarded() {
379   set_mark(mark().unset_self_forwarded());
380 }
381 
382 // The following method needs to be MT safe.
383 uint oopDesc::age() const {
384   markWord m = mark();
385   assert(!m.is_marked(), "Attempt to read age from forwarded mark");
386   if (m.has_displaced_mark_helper()) {
387     return m.displaced_mark_helper().age();
388   } else {
389     return m.age();
390   }
391 }
392 
393 void oopDesc::incr_age() {
394   markWord m = mark();
395   assert(!m.is_marked(), "Attempt to increment age of forwarded mark");
396   if (m.has_displaced_mark_helper()) {
397     m.set_displaced_mark_helper(m.displaced_mark_helper().incr_age());
398   } else {
399     set_mark(m.incr_age());
400   }
401 }
402 
403 template <typename OopClosureType>
404 void oopDesc::oop_iterate(OopClosureType* cl) {
405   OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass());
406 }
407 
408 template <typename OopClosureType>
409 void oopDesc::oop_iterate(OopClosureType* cl, MemRegion mr) {
410   OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass(), mr);
411 }
412 
413 template <typename OopClosureType>
414 size_t oopDesc::oop_iterate_size(OopClosureType* cl) {
415   Klass* k = klass();
416   size_t size = size_given_klass(k);
417   OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k);
418   return size;
419 }
420 
421 template <typename OopClosureType>
422 size_t oopDesc::oop_iterate_size(OopClosureType* cl, MemRegion mr) {
423   Klass* k = klass();
424   size_t size = size_given_klass(k);
425   OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k, mr);
426   return size;
427 }
428 
429 template <typename OopClosureType>
430 void oopDesc::oop_iterate_backwards(OopClosureType* cl) {
431   oop_iterate_backwards(cl, klass());
432 }
433 
434 template <typename OopClosureType>
435 void oopDesc::oop_iterate_backwards(OopClosureType* cl, Klass* k) {
436   // In this assert, we cannot safely access the Klass* with compact headers.
437   assert(k == klass(), "wrong klass");
438   OopIteratorClosureDispatch::oop_oop_iterate_backwards(cl, this, k);
439 }
440 
441 bool oopDesc::is_instanceof_or_null(oop obj, Klass* klass) {
442   return obj == nullptr || obj->klass()->is_subtype_of(klass);
443 }
444 
445 intptr_t oopDesc::identity_hash() {
446   // Fast case; if the object is unlocked and the hash value is set, no locking is needed
447   // Note: The mark must be read into local variable to avoid concurrent updates.
448   markWord mrk = mark();
449   if (mrk.is_unlocked() && !mrk.has_no_hash()) {
450     return mrk.hash();
451   } else if (mrk.is_marked()) {
452     return mrk.hash();
453   } else {
454     return slow_identity_hash();
455   }
456 }
457 
458 // This checks fast simple case of whether the oop has_no_hash,
459 // to optimize JVMTI table lookup.
460 bool oopDesc::fast_no_hash_check() {
461   markWord mrk = mark_acquire();
462   assert(!mrk.is_marked(), "should never be marked");
463   return mrk.is_unlocked() && mrk.has_no_hash();
464 }
465 
466 bool oopDesc::has_displaced_mark() const {
467   return mark().has_displaced_mark_helper();
468 }
469 
470 markWord oopDesc::displaced_mark() const {
471   return mark().displaced_mark_helper();
472 }
473 
474 void oopDesc::set_displaced_mark(markWord m) {
475   mark().set_displaced_mark_helper(m);
476 }
477 
478 bool oopDesc::mark_must_be_preserved() const {
479   return mark_must_be_preserved(mark());
480 }
481 
482 bool oopDesc::mark_must_be_preserved(markWord m) const {
483   return m.must_be_preserved();
484 }
485 
486 #endif // SHARE_OOPS_OOP_INLINE_HPP
--- EOF ---