1 /*
  2  * Copyright (c) 1997, 2022, Oracle and/or its affiliates. All rights reserved.
  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  *
 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,
 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
 20  * or visit www.oracle.com if you need additional information or have any
 21  * questions.
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 23  */
 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/instanceKlass.hpp"
 36 #include "oops/markWord.hpp"
 37 #include "oops/oopsHierarchy.hpp"
 38 #include "runtime/atomic.hpp"
 39 #include "runtime/globals.hpp"
 40 #include "utilities/align.hpp"
 41 #include "utilities/debug.hpp"
 42 #include "utilities/macros.hpp"
 43 #include "utilities/globalDefinitions.hpp"
 44 
 45 // Implementation of all inlined member functions defined in oop.hpp
 46 // We need a separate file to avoid circular references
 47 
 48 markWord oopDesc::mark() const {
 49   return Atomic::load(&_mark);
 50 }
 51 
 52 markWord oopDesc::mark_acquire() const {
 53   return Atomic::load_acquire(&_mark);
 54 }
 55 
 56 markWord* oopDesc::mark_addr() const {
 57   return (markWord*) &_mark;
 58 }
 59 
 60 void oopDesc::set_mark(markWord m) {
 61   Atomic::store(&_mark, m);
 62 }
 63 
 64 void oopDesc::set_mark(HeapWord* mem, markWord m) {
 65   *(markWord*)(((char*)mem) + mark_offset_in_bytes()) = m;
 66 }
 67 
 68 void oopDesc::release_set_mark(markWord m) {
 69   Atomic::release_store(&_mark, m);
 70 }
 71 
 72 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark) {
 73   return Atomic::cmpxchg(&_mark, old_mark, new_mark);
 74 }
 75 
 76 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark, atomic_memory_order order) {
 77   return Atomic::cmpxchg(&_mark, old_mark, new_mark, order);
 78 }
 79 
 80 void oopDesc::init_mark() {
 81   set_mark(Klass::default_prototype_header(klass()));
 82 }
 83 
 84 Klass* oopDesc::klass() const {
 85   if (UseCompressedClassPointers) {
 86     return CompressedKlassPointers::decode_not_null(_metadata._compressed_klass);
 87   } else {
 88     return _metadata._klass;
 89   }
 90 }
 91 
 92 Klass* oopDesc::klass_or_null() const {
 93   if (UseCompressedClassPointers) {
 94     return CompressedKlassPointers::decode(_metadata._compressed_klass);
 95   } else {
 96     return _metadata._klass;
 97   }
 98 }
 99 
100 Klass* oopDesc::klass_or_null_acquire() const {
101   if (UseCompressedClassPointers) {
102     narrowKlass nklass = Atomic::load_acquire(&_metadata._compressed_klass);
103     return CompressedKlassPointers::decode(nklass);
104   } else {
105     return Atomic::load_acquire(&_metadata._klass);
106   }
107 }
108 
109 void oopDesc::set_klass(Klass* k) {
110   assert(Universe::is_bootstrapping() || (k != NULL && k->is_klass()), "incorrect Klass");
111   if (UseCompressedClassPointers) {
112     _metadata._compressed_klass = CompressedKlassPointers::encode_not_null(k);
113   } else {
114     _metadata._klass = k;
115   }
116 }
117 
118 void oopDesc::release_set_klass(HeapWord* mem, Klass* k) {
119   assert(Universe::is_bootstrapping() || (k != NULL && k->is_klass()), "incorrect Klass");
120   char* raw_mem = ((char*)mem + klass_offset_in_bytes());
121   if (UseCompressedClassPointers) {
122     Atomic::release_store((narrowKlass*)raw_mem,
123                           CompressedKlassPointers::encode_not_null(k));
124   } else {
125     Atomic::release_store((Klass**)raw_mem, k);
126   }
127 }
128 
129 void oopDesc::set_klass_gap(HeapWord* mem, int v) {
130   if (UseCompressedClassPointers) {
131     *(int*)(((char*)mem) + klass_gap_offset_in_bytes()) = v;
132   }
133 }
134 
135 bool oopDesc::is_a(Klass* k) const {
136   return klass()->is_subtype_of(k);
137 }
138 
139 size_t oopDesc::size()  {
140   return size_given_klass(klass());
141 }
142 
143 size_t oopDesc::size_given_klass(Klass* klass)  {
144   int lh = klass->layout_helper();
145   size_t s;
146 
147   // lh is now a value computed at class initialization that may hint
148   // at the size.  For instances, this is positive and equal to the
149   // size.  For arrays, this is negative and provides log2 of the
150   // array element size.  For other oops, it is zero and thus requires
151   // a virtual call.
152   //
153   // We go to all this trouble because the size computation is at the
154   // heart of phase 2 of mark-compaction, and called for every object,
155   // alive or dead.  So the speed here is equal in importance to the
156   // speed of allocation.
157 
158   if (lh > Klass::_lh_neutral_value) {
159     if (!Klass::layout_helper_needs_slow_path(lh)) {
160       s = lh >> LogHeapWordSize;  // deliver size scaled by wordSize
161     } else {
162       s = klass->oop_size(this);
163     }
164   } else if (lh <= Klass::_lh_neutral_value) {
165     // The most common case is instances; fall through if so.
166     if (lh < Klass::_lh_neutral_value) {
167       // Second most common case is arrays.  We have to fetch the
168       // length of the array, shift (multiply) it appropriately,
169       // up to wordSize, add the header, and align to object size.
170       size_t size_in_bytes;
171       size_t array_length = (size_t) ((arrayOop)this)->length();
172       size_in_bytes = array_length << Klass::layout_helper_log2_element_size(lh);
173       size_in_bytes += Klass::layout_helper_header_size(lh);
174 
175       // This code could be simplified, but by keeping array_header_in_bytes
176       // in units of bytes and doing it this way we can round up just once,
177       // skipping the intermediate round to HeapWordSize.
178       s = align_up(size_in_bytes, MinObjAlignmentInBytes) / HeapWordSize;
179 
180       assert(s == klass->oop_size(this) || size_might_change(), "wrong array object size");
181     } else {
182       // Must be zero, so bite the bullet and take the virtual call.
183       s = klass->oop_size(this);
184     }
185   }
186 
187   assert(s > 0, "Oop size must be greater than zero, not " SIZE_FORMAT, s);
188   assert(is_object_aligned(s), "Oop size is not properly aligned: " SIZE_FORMAT, s);
189   return s;
190 }
191 
192 bool oopDesc::is_instance()    const { return klass()->is_instance_klass();             }
193 bool oopDesc::is_instanceRef() const { return klass()->is_reference_instance_klass();   }
194 bool oopDesc::is_stackChunk()  const { return klass()->is_stack_chunk_instance_klass(); }
195 bool oopDesc::is_array()       const { return klass()->is_array_klass();                }
196 bool oopDesc::is_objArray()    const { return klass()->is_objArray_klass();             }
197 bool oopDesc::is_typeArray()   const { return klass()->is_typeArray_klass();            }
198 
199 bool oopDesc::is_inline_type() const { return mark().is_inline_type(); }
200 #ifdef _LP64
201 bool oopDesc::is_flatArray() const {
202   markWord mrk = mark();
203   return (mrk.is_unlocked()) ? mrk.is_flat_array() : klass()->is_flatArray_klass();
204 }
205 bool oopDesc::is_null_free_array() const {
206   markWord mrk = mark();
207   return (mrk.is_unlocked()) ? mrk.is_null_free_array() : klass()->is_null_free_array_klass();
208 }
209 #else
210 bool oopDesc::is_flatArray()       const { return klass()->is_flatArray_klass(); }
211 bool oopDesc::is_null_free_array() const { return klass()->is_null_free_array_klass(); }
212 #endif
213 
214 template<typename T>
215 T*       oopDesc::field_addr(int offset)     const { return reinterpret_cast<T*>(cast_from_oop<intptr_t>(as_oop()) + offset); }
216 
217 template <typename T>
218 size_t   oopDesc::field_offset(T* p) const { return pointer_delta((void*)p, (void*)this, 1); }
219 
220 template <DecoratorSet decorators>
221 inline oop  oopDesc::obj_field_access(int offset) const             { return HeapAccess<decorators>::oop_load_at(as_oop(), offset); }
222 inline oop  oopDesc::obj_field(int offset) const                    { return HeapAccess<>::oop_load_at(as_oop(), offset);  }
223 
224 inline void oopDesc::obj_field_put(int offset, oop value)           { HeapAccess<>::oop_store_at(as_oop(), offset, value); }
225 template <DecoratorSet decorators>
226 inline void oopDesc::obj_field_put_access(int offset, oop value)    { HeapAccess<decorators>::oop_store_at(as_oop(), offset, value); }
227 
228 inline jbyte oopDesc::byte_field(int offset) const                  { return *field_addr<jbyte>(offset);  }
229 inline void  oopDesc::byte_field_put(int offset, jbyte value)       { *field_addr<jbyte>(offset) = value; }
230 
231 inline jchar oopDesc::char_field(int offset) const                  { return *field_addr<jchar>(offset);  }
232 inline void  oopDesc::char_field_put(int offset, jchar value)       { *field_addr<jchar>(offset) = value; }
233 
234 inline jboolean oopDesc::bool_field(int offset) const               { return *field_addr<jboolean>(offset); }
235 inline void     oopDesc::bool_field_put(int offset, jboolean value) { *field_addr<jboolean>(offset) = jboolean(value & 1); }
236 inline jboolean oopDesc::bool_field_volatile(int offset) const      { return RawAccess<MO_SEQ_CST>::load(field_addr<jboolean>(offset)); }
237 inline void     oopDesc::bool_field_put_volatile(int offset, jboolean value) { RawAccess<MO_SEQ_CST>::store(field_addr<jboolean>(offset), jboolean(value & 1)); }
238 inline jshort oopDesc::short_field(int offset) const                { return *field_addr<jshort>(offset);   }
239 inline void   oopDesc::short_field_put(int offset, jshort value)    { *field_addr<jshort>(offset) = value;  }
240 
241 inline jint oopDesc::int_field(int offset) const                    { return *field_addr<jint>(offset);     }
242 inline void oopDesc::int_field_put(int offset, jint value)          { *field_addr<jint>(offset) = value;    }
243 
244 inline jlong oopDesc::long_field(int offset) const                  { return *field_addr<jlong>(offset);    }
245 inline void  oopDesc::long_field_put(int offset, jlong value)       { *field_addr<jlong>(offset) = value;   }
246 
247 inline jfloat oopDesc::float_field(int offset) const                { return *field_addr<jfloat>(offset);   }
248 inline void   oopDesc::float_field_put(int offset, jfloat value)    { *field_addr<jfloat>(offset) = value;  }
249 
250 inline jdouble oopDesc::double_field(int offset) const              { return *field_addr<jdouble>(offset);  }
251 inline void    oopDesc::double_field_put(int offset, jdouble value) { *field_addr<jdouble>(offset) = value; }
252 
253 bool oopDesc::is_locked() const {
254   return mark().is_locked();
255 }
256 
257 bool oopDesc::is_unlocked() const {
258   return mark().is_unlocked();
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 reversible");
278   set_mark(m);
279 }
280 
281 oop oopDesc::forward_to_atomic(oop p, markWord compare, atomic_memory_order order) {
282   verify_forwardee(p);
283   markWord m = markWord::encode_pointer_as_mark(p);
284   assert(m.decode_pointer() == p, "encoding must be reversible");
285   markWord old_mark = cas_set_mark(m, compare, order);
286   if (old_mark == compare) {
287     return NULL;
288   } else {
289     return cast_to_oop(old_mark.decode_pointer());
290   }
291 }
292 
293 // Note that the forwardee is not the same thing as the displaced_mark.
294 // The forwardee is used when copying during scavenge and mark-sweep.
295 // It does need to clear the low two locking- and GC-related bits.
296 oop oopDesc::forwardee() const {
297   assert(is_forwarded(), "only decode when actually forwarded");
298   return cast_to_oop(mark().decode_pointer());
299 }
300 
301 // The following method needs to be MT safe.
302 uint oopDesc::age() const {
303   assert(!mark().is_marked(), "Attempt to read age from forwarded mark");
304   if (has_displaced_mark()) {
305     return displaced_mark().age();
306   } else {
307     return mark().age();
308   }
309 }
310 
311 void oopDesc::incr_age() {
312   assert(!mark().is_marked(), "Attempt to increment age of forwarded mark");
313   if (has_displaced_mark()) {
314     set_displaced_mark(displaced_mark().incr_age());
315   } else {
316     set_mark(mark().incr_age());
317   }
318 }
319 
320 template <typename OopClosureType>
321 void oopDesc::oop_iterate(OopClosureType* cl) {
322   OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass());
323 }
324 
325 template <typename OopClosureType>
326 void oopDesc::oop_iterate(OopClosureType* cl, MemRegion mr) {
327   OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass(), mr);
328 }
329 
330 template <typename OopClosureType>
331 size_t oopDesc::oop_iterate_size(OopClosureType* cl) {
332   Klass* k = klass();
333   size_t size = size_given_klass(k);
334   OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k);
335   return size;
336 }
337 
338 template <typename OopClosureType>
339 size_t oopDesc::oop_iterate_size(OopClosureType* cl, MemRegion mr) {
340   Klass* k = klass();
341   size_t size = size_given_klass(k);
342   OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k, mr);
343   return size;
344 }
345 
346 template <typename OopClosureType>
347 void oopDesc::oop_iterate_backwards(OopClosureType* cl) {
348   oop_iterate_backwards(cl, klass());
349 }
350 
351 template <typename OopClosureType>
352 void oopDesc::oop_iterate_backwards(OopClosureType* cl, Klass* k) {
353   assert(k == klass(), "wrong klass");
354   OopIteratorClosureDispatch::oop_oop_iterate_backwards(cl, this, k);
355 }
356 
357 bool oopDesc::is_instanceof_or_null(oop obj, Klass* klass) {
358   return obj == NULL || obj->klass()->is_subtype_of(klass);
359 }
360 
361 intptr_t oopDesc::identity_hash() {
362   // Fast case; if the object is unlocked and the hash value is set, no locking is needed
363   // Note: The mark must be read into local variable to avoid concurrent updates.
364   markWord mrk = mark();
365   if (mrk.is_unlocked() && !mrk.has_no_hash()) {
366     return mrk.hash();
367   } else if (mrk.is_marked()) {
368     return mrk.hash();
369   } else {
370     return slow_identity_hash();
371   }
372 }
373 
374 bool oopDesc::has_displaced_mark() const {
375   return mark().has_displaced_mark_helper();
376 }
377 
378 markWord oopDesc::displaced_mark() const {
379   return mark().displaced_mark_helper();
380 }
381 
382 void oopDesc::set_displaced_mark(markWord m) {
383   mark().set_displaced_mark_helper(m);
384 }
385 
386 bool oopDesc::mark_must_be_preserved() const {
387   return mark_must_be_preserved(mark());
388 }
389 
390 bool oopDesc::mark_must_be_preserved(markWord m) const {
391   return m.must_be_preserved(this);
392 }
393 
394 #endif // SHARE_OOPS_OOP_INLINE_HPP