1 /*
   2  * Copyright (c) 1997, 2016, 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.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_OOPS_OOP_INLINE_HPP
  26 #define SHARE_VM_OOPS_OOP_INLINE_HPP
  27 
  28 #include "gc/shared/ageTable.hpp"
  29 #include "gc/shared/barrierSet.inline.hpp"
  30 #include "gc/shared/cardTableModRefBS.hpp"
  31 #include "gc/shared/collectedHeap.inline.hpp"
  32 #include "gc/shared/genCollectedHeap.hpp"
  33 #include "gc/shared/generation.hpp"
  34 #include "oops/arrayKlass.hpp"
  35 #include "oops/arrayOop.hpp"
  36 #include "oops/klass.inline.hpp"
  37 #include "oops/markOop.inline.hpp"
  38 #include "oops/oop.hpp"
  39 #include "runtime/atomic.inline.hpp"
  40 #include "runtime/orderAccess.inline.hpp"
  41 #include "runtime/os.hpp"
  42 #include "utilities/macros.hpp"
  43 
  44 inline void update_barrier_set(void* p, oop v, bool release = false) {
  45   assert(oopDesc::bs() != NULL, "Uninitialized bs in oop!");
  46   oopDesc::bs()->write_ref_field(p, v, release);
  47 }
  48 
  49 template <class T> inline void update_barrier_set_pre(T* p, oop v) {
  50   oopDesc::bs()->write_ref_field_pre(p, v);
  51 }
  52 
  53 template <class T> void oop_store(T* p, oop v) {
  54   if (always_do_update_barrier) {
  55     oop_store((volatile T*)p, v);
  56   } else {
  57     update_barrier_set_pre(p, v);
  58     oopDesc::encode_store_heap_oop(p, v);
  59     // always_do_update_barrier == false =>
  60     // Either we are at a safepoint (in GC) or CMS is not used. In both
  61     // cases it's unnecessary to mark the card as dirty with release sematics.
  62     update_barrier_set((void*)p, v, false /* release */);  // cast away type
  63   }
  64 }
  65 
  66 template <class T> void oop_store(volatile T* p, oop v) {
  67   update_barrier_set_pre((T*)p, v);   // cast away volatile
  68   // Used by release_obj_field_put, so use release_store_ptr.
  69   oopDesc::release_encode_store_heap_oop(p, v);
  70   // When using CMS we must mark the card corresponding to p as dirty
  71   // with release sematics to prevent that CMS sees the dirty card but
  72   // not the new value v at p due to reordering of the two
  73   // stores. Note that CMS has a concurrent precleaning phase, where
  74   // it reads the card table while the Java threads are running.
  75   update_barrier_set((void*)p, v, true /* release */);    // cast away type
  76 }
  77 
  78 // Should replace *addr = oop assignments where addr type depends on UseCompressedOops
  79 // (without having to remember the function name this calls).
  80 inline void oop_store_raw(HeapWord* addr, oop value) {
  81   if (UseCompressedOops) {
  82     oopDesc::encode_store_heap_oop((narrowOop*)addr, value);
  83   } else {
  84     oopDesc::encode_store_heap_oop((oop*)addr, value);
  85   }
  86 }
  87 
  88 // Implementation of all inlined member functions defined in oop.hpp
  89 // We need a separate file to avoid circular references
  90 
  91 void oopDesc::release_set_mark(markOop m) {
  92   OrderAccess::release_store_ptr(&_mark, m);
  93 }
  94 
  95 markOop oopDesc::cas_set_mark(markOop new_mark, markOop old_mark) {
  96   return (markOop) Atomic::cmpxchg_ptr(new_mark, &_mark, old_mark);
  97 }
  98 
  99 void oopDesc::init_mark() {
 100   set_mark(markOopDesc::prototype_for_object(this));
 101 }
 102 
 103 Klass* oopDesc::klass() const {
 104   if (UseCompressedClassPointers) {
 105     return Klass::decode_klass_not_null(_metadata._compressed_klass);
 106   } else {
 107     return _metadata._klass;
 108   }
 109 }
 110 
 111 Klass* oopDesc::klass_or_null() const volatile {
 112   // can be NULL in CMS
 113   if (UseCompressedClassPointers) {
 114     return Klass::decode_klass(_metadata._compressed_klass);
 115   } else {
 116     return _metadata._klass;
 117   }
 118 }
 119 
 120 Klass** oopDesc::klass_addr() {
 121   // Only used internally and with CMS and will not work with
 122   // UseCompressedOops
 123   assert(!UseCompressedClassPointers, "only supported with uncompressed klass pointers");
 124   return (Klass**) &_metadata._klass;
 125 }
 126 
 127 narrowKlass* oopDesc::compressed_klass_addr() {
 128   assert(UseCompressedClassPointers, "only called by compressed klass pointers");
 129   return &_metadata._compressed_klass;
 130 }
 131 
 132 void oopDesc::set_klass(Klass* k) {
 133   // since klasses are promoted no store check is needed
 134   assert(Universe::is_bootstrapping() || k != NULL, "must be a real Klass*");
 135   assert(Universe::is_bootstrapping() || k->is_klass(), "not a Klass*");
 136   if (UseCompressedClassPointers) {
 137     *compressed_klass_addr() = Klass::encode_klass_not_null(k);
 138   } else {
 139     *klass_addr() = k;
 140   }
 141 }
 142 
 143 int oopDesc::klass_gap() const {
 144   return *(int*)(((intptr_t)this) + klass_gap_offset_in_bytes());
 145 }
 146 
 147 void oopDesc::set_klass_gap(int v) {
 148   if (UseCompressedClassPointers) {
 149     *(int*)(((intptr_t)this) + klass_gap_offset_in_bytes()) = v;
 150   }
 151 }
 152 
 153 void oopDesc::set_klass_to_list_ptr(oop k) {
 154   // This is only to be used during GC, for from-space objects, so no
 155   // barrier is needed.
 156   if (UseCompressedClassPointers) {
 157     _metadata._compressed_klass = (narrowKlass)encode_heap_oop(k);  // may be null (parnew overflow handling)
 158   } else {
 159     _metadata._klass = (Klass*)(address)k;
 160   }
 161 }
 162 
 163 oop oopDesc::list_ptr_from_klass() {
 164   // This is only to be used during GC, for from-space objects.
 165   if (UseCompressedClassPointers) {
 166     return decode_heap_oop((narrowOop)_metadata._compressed_klass);
 167   } else {
 168     // Special case for GC
 169     return (oop)(address)_metadata._klass;
 170   }
 171 }
 172 
 173 bool oopDesc::is_a(Klass* k) const {
 174   return klass()->is_subtype_of(k);
 175 }
 176 
 177 int oopDesc::size()  {
 178   return size_given_klass(klass());
 179 }
 180 
 181 int oopDesc::size_given_klass(Klass* klass)  {
 182   int lh = klass->layout_helper();
 183   int s;
 184 
 185   // lh is now a value computed at class initialization that may hint
 186   // at the size.  For instances, this is positive and equal to the
 187   // size.  For arrays, this is negative and provides log2 of the
 188   // array element size.  For other oops, it is zero and thus requires
 189   // a virtual call.
 190   //
 191   // We go to all this trouble because the size computation is at the
 192   // heart of phase 2 of mark-compaction, and called for every object,
 193   // alive or dead.  So the speed here is equal in importance to the
 194   // speed of allocation.
 195 
 196   if (lh > Klass::_lh_neutral_value) {
 197     if (!Klass::layout_helper_needs_slow_path(lh)) {
 198       s = lh >> LogHeapWordSize;  // deliver size scaled by wordSize
 199     } else {
 200       s = klass->oop_size(this);
 201     }
 202   } else if (lh <= Klass::_lh_neutral_value) {
 203     // The most common case is instances; fall through if so.
 204     if (lh < Klass::_lh_neutral_value) {
 205       // Second most common case is arrays.  We have to fetch the
 206       // length of the array, shift (multiply) it appropriately,
 207       // up to wordSize, add the header, and align to object size.
 208       size_t size_in_bytes;
 209 #ifdef _M_IA64
 210       // The Windows Itanium Aug 2002 SDK hoists this load above
 211       // the check for s < 0.  An oop at the end of the heap will
 212       // cause an access violation if this load is performed on a non
 213       // array oop.  Making the reference volatile prohibits this.
 214       // (%%% please explain by what magic the length is actually fetched!)
 215       volatile int *array_length;
 216       array_length = (volatile int *)( (intptr_t)this +
 217                           arrayOopDesc::length_offset_in_bytes() );
 218       assert(array_length > 0, "Integer arithmetic problem somewhere");
 219       // Put into size_t to avoid overflow.
 220       size_in_bytes = (size_t) array_length;
 221       size_in_bytes = size_in_bytes << Klass::layout_helper_log2_element_size(lh);
 222 #else
 223       size_t array_length = (size_t) ((arrayOop)this)->length();
 224       size_in_bytes = array_length << Klass::layout_helper_log2_element_size(lh);
 225 #endif
 226       size_in_bytes += Klass::layout_helper_header_size(lh);
 227 
 228       // This code could be simplified, but by keeping array_header_in_bytes
 229       // in units of bytes and doing it this way we can round up just once,
 230       // skipping the intermediate round to HeapWordSize.  Cast the result
 231       // of round_to to size_t to guarantee unsigned division == right shift.
 232       s = (int)((size_t)round_to(size_in_bytes, MinObjAlignmentInBytes) /
 233         HeapWordSize);
 234 
 235       // ParNew (used by CMS), UseParallelGC and UseG1GC can change the length field
 236       // of an "old copy" of an object array in the young gen so it indicates
 237       // the grey portion of an already copied array. This will cause the first
 238       // disjunct below to fail if the two comparands are computed across such
 239       // a concurrent change.
 240       // ParNew also runs with promotion labs (which look like int
 241       // filler arrays) which are subject to changing their declared size
 242       // when finally retiring a PLAB; this also can cause the first disjunct
 243       // to fail for another worker thread that is concurrently walking the block
 244       // offset table. Both these invariant failures are benign for their
 245       // current uses; we relax the assertion checking to cover these two cases below:
 246       //     is_objArray() && is_forwarded()   // covers first scenario above
 247       //  || is_typeArray()                    // covers second scenario above
 248       // If and when UseParallelGC uses the same obj array oop stealing/chunking
 249       // technique, we will need to suitably modify the assertion.
 250       assert((s == klass->oop_size(this)) ||
 251              (Universe::heap()->is_gc_active() &&
 252               ((is_typeArray() && UseConcMarkSweepGC) ||
 253                (is_objArray()  && is_forwarded() && (UseConcMarkSweepGC || UseParallelGC || UseG1GC)))),
 254              "wrong array object size");
 255     } else {
 256       // Must be zero, so bite the bullet and take the virtual call.
 257       s = klass->oop_size(this);
 258     }
 259   }
 260 
 261   assert(s % MinObjAlignment == 0, "alignment check");
 262   assert(s > 0, "Bad size calculated");
 263   return s;
 264 }
 265 
 266 bool oopDesc::is_instance()  const { return klass()->is_instance_klass();  }
 267 bool oopDesc::is_array()     const { return klass()->is_array_klass();     }
 268 bool oopDesc::is_objArray()  const { return klass()->is_objArray_klass();  }
 269 bool oopDesc::is_typeArray() const { return klass()->is_typeArray_klass(); }
 270 
 271 void*      oopDesc::field_base(int offset)          const { return (void*)&((char*)this)[offset]; }
 272 
 273 jbyte*     oopDesc::byte_field_addr(int offset)     const { return (jbyte*)    field_base(offset); }
 274 jchar*     oopDesc::char_field_addr(int offset)     const { return (jchar*)    field_base(offset); }
 275 jboolean*  oopDesc::bool_field_addr(int offset)     const { return (jboolean*) field_base(offset); }
 276 jint*      oopDesc::int_field_addr(int offset)      const { return (jint*)     field_base(offset); }
 277 jshort*    oopDesc::short_field_addr(int offset)    const { return (jshort*)   field_base(offset); }
 278 jlong*     oopDesc::long_field_addr(int offset)     const { return (jlong*)    field_base(offset); }
 279 jfloat*    oopDesc::float_field_addr(int offset)    const { return (jfloat*)   field_base(offset); }
 280 jdouble*   oopDesc::double_field_addr(int offset)   const { return (jdouble*)  field_base(offset); }
 281 Metadata** oopDesc::metadata_field_addr(int offset) const { return (Metadata**)field_base(offset); }
 282 
 283 template <class T> T* oopDesc::obj_field_addr(int offset) const { return (T*)  field_base(offset); }
 284 address*   oopDesc::address_field_addr(int offset)  const { return (address*)  field_base(offset); }
 285 
 286 
 287 // Functions for getting and setting oops within instance objects.
 288 // If the oops are compressed, the type passed to these overloaded functions
 289 // is narrowOop.  All functions are overloaded so they can be called by
 290 // template functions without conditionals (the compiler instantiates via
 291 // the right type and inlines the appopriate code).
 292 
 293 // Algorithm for encoding and decoding oops from 64 bit pointers to 32 bit
 294 // offset from the heap base.  Saving the check for null can save instructions
 295 // in inner GC loops so these are separated.
 296 
 297 inline bool check_obj_alignment(oop obj) {
 298   return (cast_from_oop<intptr_t>(obj) & MinObjAlignmentInBytesMask) == 0;
 299 }
 300 
 301 oop oopDesc::decode_heap_oop_not_null(narrowOop v) {
 302   assert(!is_null(v), "narrow oop value can never be zero");
 303   address base = Universe::narrow_oop_base();
 304   int    shift = Universe::narrow_oop_shift();
 305   oop result = (oop)(void*)((uintptr_t)base + ((uintptr_t)v << shift));
 306   assert(check_obj_alignment(result), "address not aligned: " INTPTR_FORMAT, p2i((void*) result));
 307   return result;
 308 }
 309 
 310 oop oopDesc::decode_heap_oop(narrowOop v) {
 311   return is_null(v) ? (oop)NULL : decode_heap_oop_not_null(v);
 312 }
 313 
 314 narrowOop oopDesc::encode_heap_oop_not_null(oop v) {
 315   assert(!is_null(v), "oop value can never be zero");
 316   assert(check_obj_alignment(v), "Address not aligned");
 317   assert(Universe::heap()->is_in_reserved(v), "Address not in heap");
 318   address base = Universe::narrow_oop_base();
 319   int    shift = Universe::narrow_oop_shift();
 320   uint64_t  pd = (uint64_t)(pointer_delta((void*)v, (void*)base, 1));
 321   assert(OopEncodingHeapMax > pd, "change encoding max if new encoding");
 322   uint64_t result = pd >> shift;
 323   assert((result & CONST64(0xffffffff00000000)) == 0, "narrow oop overflow");
 324   assert(decode_heap_oop(result) == v, "reversibility");
 325   return (narrowOop)result;
 326 }
 327 
 328 narrowOop oopDesc::encode_heap_oop(oop v) {
 329   return (is_null(v)) ? (narrowOop)0 : encode_heap_oop_not_null(v);
 330 }
 331 
 332 // Load and decode an oop out of the Java heap into a wide oop.
 333 oop oopDesc::load_decode_heap_oop_not_null(narrowOop* p) {
 334   return decode_heap_oop_not_null(*p);
 335 }
 336 
 337 // Load and decode an oop out of the heap accepting null
 338 oop oopDesc::load_decode_heap_oop(narrowOop* p) {
 339   return decode_heap_oop(*p);
 340 }
 341 
 342 // Encode and store a heap oop.
 343 void oopDesc::encode_store_heap_oop_not_null(narrowOop* p, oop v) {
 344   *p = encode_heap_oop_not_null(v);
 345 }
 346 
 347 // Encode and store a heap oop allowing for null.
 348 void oopDesc::encode_store_heap_oop(narrowOop* p, oop v) {
 349   *p = encode_heap_oop(v);
 350 }
 351 
 352 // Store heap oop as is for volatile fields.
 353 void oopDesc::release_store_heap_oop(volatile oop* p, oop v) {
 354   OrderAccess::release_store_ptr(p, v);
 355 }
 356 void oopDesc::release_store_heap_oop(volatile narrowOop* p, narrowOop v) {
 357   OrderAccess::release_store(p, v);
 358 }
 359 
 360 void oopDesc::release_encode_store_heap_oop_not_null(volatile narrowOop* p, oop v) {
 361   // heap oop is not pointer sized.
 362   OrderAccess::release_store(p, encode_heap_oop_not_null(v));
 363 }
 364 void oopDesc::release_encode_store_heap_oop_not_null(volatile oop* p, oop v) {
 365   OrderAccess::release_store_ptr(p, v);
 366 }
 367 
 368 void oopDesc::release_encode_store_heap_oop(volatile oop* p, oop v) {
 369   OrderAccess::release_store_ptr(p, v);
 370 }
 371 void oopDesc::release_encode_store_heap_oop(volatile narrowOop* p, oop v) {
 372   OrderAccess::release_store(p, encode_heap_oop(v));
 373 }
 374 
 375 // These functions are only used to exchange oop fields in instances,
 376 // not headers.
 377 oop oopDesc::atomic_exchange_oop(oop exchange_value, volatile HeapWord *dest) {
 378   if (UseCompressedOops) {
 379     // encode exchange value from oop to T
 380     narrowOop val = encode_heap_oop(exchange_value);
 381     narrowOop old = (narrowOop)Atomic::xchg(val, (narrowOop*)dest);
 382     // decode old from T to oop
 383     return decode_heap_oop(old);
 384   } else {
 385     return (oop)Atomic::xchg_ptr(exchange_value, (oop*)dest);
 386   }
 387 }
 388 
 389 oop oopDesc::atomic_compare_exchange_oop(oop exchange_value,
 390                                          volatile HeapWord *dest,
 391                                          oop compare_value,
 392                                          bool prebarrier) {
 393   if (UseCompressedOops) {
 394     if (prebarrier) {
 395       update_barrier_set_pre((narrowOop*)dest, exchange_value);
 396     }
 397     // encode exchange and compare value from oop to T
 398     narrowOop val = encode_heap_oop(exchange_value);
 399     narrowOop cmp = encode_heap_oop(compare_value);
 400 
 401     narrowOop old = (narrowOop) Atomic::cmpxchg(val, (narrowOop*)dest, cmp);
 402     // decode old from T to oop
 403     return decode_heap_oop(old);
 404   } else {
 405     if (prebarrier) {
 406       update_barrier_set_pre((oop*)dest, exchange_value);
 407     }
 408     return (oop)Atomic::cmpxchg_ptr(exchange_value, (oop*)dest, compare_value);
 409   }
 410 }
 411 
 412 // In order to put or get a field out of an instance, must first check
 413 // if the field has been compressed and uncompress it.
 414 oop oopDesc::obj_field(int offset) const {
 415   return UseCompressedOops ?
 416     load_decode_heap_oop(obj_field_addr<narrowOop>(offset)) :
 417     load_decode_heap_oop(obj_field_addr<oop>(offset));
 418 }
 419 
 420 void oopDesc::obj_field_put(int offset, oop value) {
 421   UseCompressedOops ? oop_store(obj_field_addr<narrowOop>(offset), value) :
 422                       oop_store(obj_field_addr<oop>(offset),       value);
 423 }
 424 
 425 void oopDesc::obj_field_put_raw(int offset, oop value) {
 426   UseCompressedOops ?
 427     encode_store_heap_oop(obj_field_addr<narrowOop>(offset), value) :
 428     encode_store_heap_oop(obj_field_addr<oop>(offset),       value);
 429 }
 430 void oopDesc::obj_field_put_volatile(int offset, oop value) {
 431   OrderAccess::release();
 432   obj_field_put(offset, value);
 433   OrderAccess::fence();
 434 }
 435 
 436 Metadata* oopDesc::metadata_field(int offset) const           { return *metadata_field_addr(offset);   }
 437 void oopDesc::metadata_field_put(int offset, Metadata* value) { *metadata_field_addr(offset) = value;  }
 438 
 439 jbyte oopDesc::byte_field(int offset) const                   { return (jbyte) *byte_field_addr(offset);    }
 440 void oopDesc::byte_field_put(int offset, jbyte contents)      { *byte_field_addr(offset) = (jint) contents; }
 441 
 442 jchar oopDesc::char_field(int offset) const                   { return (jchar) *char_field_addr(offset);    }
 443 void oopDesc::char_field_put(int offset, jchar contents)      { *char_field_addr(offset) = (jint) contents; }
 444 
 445 jboolean oopDesc::bool_field(int offset) const                { return (jboolean) *bool_field_addr(offset); }
 446 void oopDesc::bool_field_put(int offset, jboolean contents)   { *bool_field_addr(offset) = (((jint) contents) & 1); }
 447 
 448 jint oopDesc::int_field(int offset) const                     { return *int_field_addr(offset);        }
 449 void oopDesc::int_field_put(int offset, jint contents)        { *int_field_addr(offset) = contents;    }
 450 
 451 jshort oopDesc::short_field(int offset) const                 { return (jshort) *short_field_addr(offset);  }
 452 void oopDesc::short_field_put(int offset, jshort contents)    { *short_field_addr(offset) = (jint) contents;}
 453 
 454 jlong oopDesc::long_field(int offset) const                   { return *long_field_addr(offset);       }
 455 void oopDesc::long_field_put(int offset, jlong contents)      { *long_field_addr(offset) = contents;   }
 456 
 457 jfloat oopDesc::float_field(int offset) const                 { return *float_field_addr(offset);      }
 458 void oopDesc::float_field_put(int offset, jfloat contents)    { *float_field_addr(offset) = contents;  }
 459 
 460 jdouble oopDesc::double_field(int offset) const               { return *double_field_addr(offset);     }
 461 void oopDesc::double_field_put(int offset, jdouble contents)  { *double_field_addr(offset) = contents; }
 462 
 463 address oopDesc::address_field(int offset) const              { return *address_field_addr(offset);     }
 464 void oopDesc::address_field_put(int offset, address contents) { *address_field_addr(offset) = contents; }
 465 
 466 oop oopDesc::obj_field_acquire(int offset) const {
 467   return UseCompressedOops ?
 468              decode_heap_oop((narrowOop)
 469                OrderAccess::load_acquire(obj_field_addr<narrowOop>(offset)))
 470            : decode_heap_oop((oop)
 471                OrderAccess::load_ptr_acquire(obj_field_addr<oop>(offset)));
 472 }
 473 void oopDesc::release_obj_field_put(int offset, oop value) {
 474   UseCompressedOops ?
 475     oop_store((volatile narrowOop*)obj_field_addr<narrowOop>(offset), value) :
 476     oop_store((volatile oop*)      obj_field_addr<oop>(offset),       value);
 477 }
 478 
 479 jbyte oopDesc::byte_field_acquire(int offset) const                   { return OrderAccess::load_acquire(byte_field_addr(offset));     }
 480 void oopDesc::release_byte_field_put(int offset, jbyte contents)      { OrderAccess::release_store(byte_field_addr(offset), contents); }
 481 
 482 jchar oopDesc::char_field_acquire(int offset) const                   { return OrderAccess::load_acquire(char_field_addr(offset));     }
 483 void oopDesc::release_char_field_put(int offset, jchar contents)      { OrderAccess::release_store(char_field_addr(offset), contents); }
 484 
 485 jboolean oopDesc::bool_field_acquire(int offset) const                { return OrderAccess::load_acquire(bool_field_addr(offset));     }
 486 void oopDesc::release_bool_field_put(int offset, jboolean contents)   { OrderAccess::release_store(bool_field_addr(offset), (contents & 1)); }
 487 
 488 jint oopDesc::int_field_acquire(int offset) const                     { return OrderAccess::load_acquire(int_field_addr(offset));      }
 489 void oopDesc::release_int_field_put(int offset, jint contents)        { OrderAccess::release_store(int_field_addr(offset), contents);  }
 490 
 491 jshort oopDesc::short_field_acquire(int offset) const                 { return (jshort)OrderAccess::load_acquire(short_field_addr(offset)); }
 492 void oopDesc::release_short_field_put(int offset, jshort contents)    { OrderAccess::release_store(short_field_addr(offset), contents);     }
 493 
 494 jlong oopDesc::long_field_acquire(int offset) const                   { return OrderAccess::load_acquire(long_field_addr(offset));       }
 495 void oopDesc::release_long_field_put(int offset, jlong contents)      { OrderAccess::release_store(long_field_addr(offset), contents);   }
 496 
 497 jfloat oopDesc::float_field_acquire(int offset) const                 { return OrderAccess::load_acquire(float_field_addr(offset));      }
 498 void oopDesc::release_float_field_put(int offset, jfloat contents)    { OrderAccess::release_store(float_field_addr(offset), contents);  }
 499 
 500 jdouble oopDesc::double_field_acquire(int offset) const               { return OrderAccess::load_acquire(double_field_addr(offset));     }
 501 void oopDesc::release_double_field_put(int offset, jdouble contents)  { OrderAccess::release_store(double_field_addr(offset), contents); }
 502 
 503 address oopDesc::address_field_acquire(int offset) const              { return (address) OrderAccess::load_ptr_acquire(address_field_addr(offset)); }
 504 void oopDesc::release_address_field_put(int offset, address contents) { OrderAccess::release_store_ptr(address_field_addr(offset), contents); }
 505 
 506 bool oopDesc::is_locked() const {
 507   return mark()->is_locked();
 508 }
 509 
 510 bool oopDesc::is_unlocked() const {
 511   return mark()->is_unlocked();
 512 }
 513 
 514 bool oopDesc::has_bias_pattern() const {
 515   return mark()->has_bias_pattern();
 516 }
 517 
 518 // used only for asserts
 519 bool oopDesc::is_oop(bool ignore_mark_word) const {
 520   oop obj = (oop) this;
 521   if (!check_obj_alignment(obj)) return false;
 522   if (!Universe::heap()->is_in_reserved(obj)) return false;
 523   // obj is aligned and accessible in heap
 524   if (Universe::heap()->is_in_reserved(obj->klass_or_null())) return false;
 525 
 526   // Header verification: the mark is typically non-NULL. If we're
 527   // at a safepoint, it must not be null.
 528   // Outside of a safepoint, the header could be changing (for example,
 529   // another thread could be inflating a lock on this object).
 530   if (ignore_mark_word) {
 531     return true;
 532   }
 533   if (mark() != NULL) {
 534     return true;
 535   }
 536   return !SafepointSynchronize::is_at_safepoint();
 537 }
 538 
 539 
 540 // used only for asserts
 541 bool oopDesc::is_oop_or_null(bool ignore_mark_word) const {
 542   return this == NULL ? true : is_oop(ignore_mark_word);
 543 }
 544 
 545 #ifndef PRODUCT
 546 // used only for asserts
 547 bool oopDesc::is_unlocked_oop() const {
 548   if (!Universe::heap()->is_in_reserved(this)) return false;
 549   return mark()->is_unlocked();
 550 }
 551 #endif // PRODUCT
 552 
 553 // Used only for markSweep, scavenging
 554 bool oopDesc::is_gc_marked() const {
 555   return mark()->is_marked();
 556 }
 557 
 558 bool oopDesc::is_scavengable() const {
 559   return Universe::heap()->is_scavengable(this);
 560 }
 561 
 562 // Used by scavengers
 563 bool oopDesc::is_forwarded() const {
 564   // The extra heap check is needed since the obj might be locked, in which case the
 565   // mark would point to a stack location and have the sentinel bit cleared
 566   return mark()->is_marked();
 567 }
 568 
 569 // Used by scavengers
 570 void oopDesc::forward_to(oop p) {
 571   assert(check_obj_alignment(p),
 572          "forwarding to something not aligned");
 573   assert(Universe::heap()->is_in_reserved(p),
 574          "forwarding to something not in heap");
 575   markOop m = markOopDesc::encode_pointer_as_mark(p);
 576   assert(m->decode_pointer() == p, "encoding must be reversable");
 577   set_mark(m);
 578 }
 579 
 580 // Used by parallel scavengers
 581 bool oopDesc::cas_forward_to(oop p, markOop compare) {
 582   assert(check_obj_alignment(p),
 583          "forwarding to something not aligned");
 584   assert(Universe::heap()->is_in_reserved(p),
 585          "forwarding to something not in heap");
 586   markOop m = markOopDesc::encode_pointer_as_mark(p);
 587   assert(m->decode_pointer() == p, "encoding must be reversable");
 588   return cas_set_mark(m, compare) == compare;
 589 }
 590 
 591 #if INCLUDE_ALL_GCS
 592 oop oopDesc::forward_to_atomic(oop p) {
 593   markOop oldMark = mark();
 594   markOop forwardPtrMark = markOopDesc::encode_pointer_as_mark(p);
 595   markOop curMark;
 596 
 597   assert(forwardPtrMark->decode_pointer() == p, "encoding must be reversable");
 598   assert(sizeof(markOop) == sizeof(intptr_t), "CAS below requires this.");
 599 
 600   while (!oldMark->is_marked()) {
 601     curMark = (markOop)Atomic::cmpxchg_ptr(forwardPtrMark, &_mark, oldMark);
 602     assert(is_forwarded(), "object should have been forwarded");
 603     if (curMark == oldMark) {
 604       return NULL;
 605     }
 606     // If the CAS was unsuccessful then curMark->is_marked()
 607     // should return true as another thread has CAS'd in another
 608     // forwarding pointer.
 609     oldMark = curMark;
 610   }
 611   return forwardee();
 612 }
 613 #endif
 614 
 615 // Note that the forwardee is not the same thing as the displaced_mark.
 616 // The forwardee is used when copying during scavenge and mark-sweep.
 617 // It does need to clear the low two locking- and GC-related bits.
 618 oop oopDesc::forwardee() const {
 619   return (oop) mark()->decode_pointer();
 620 }
 621 
 622 // The following method needs to be MT safe.
 623 uint oopDesc::age() const {
 624   assert(!is_forwarded(), "Attempt to read age from forwarded mark");
 625   if (has_displaced_mark()) {
 626     return displaced_mark()->age();
 627   } else {
 628     return mark()->age();
 629   }
 630 }
 631 
 632 void oopDesc::incr_age() {
 633   assert(!is_forwarded(), "Attempt to increment age of forwarded mark");
 634   if (has_displaced_mark()) {
 635     set_displaced_mark(displaced_mark()->incr_age());
 636   } else {
 637     set_mark(mark()->incr_age());
 638   }
 639 }
 640 
 641 int oopDesc::ms_adjust_pointers() {
 642   debug_only(int check_size = size());
 643   int s = klass()->oop_ms_adjust_pointers(this);
 644   assert(s == check_size, "should be the same");
 645   return s;
 646 }
 647 
 648 #if INCLUDE_ALL_GCS
 649 void oopDesc::pc_follow_contents(ParCompactionManager* cm) {
 650   klass()->oop_pc_follow_contents(this, cm);
 651 }
 652 
 653 void oopDesc::pc_update_contents(ParCompactionManager* cm) {
 654   Klass* k = klass();
 655   if (!k->is_typeArray_klass()) {
 656     // It might contain oops beyond the header, so take the virtual call.
 657     k->oop_pc_update_pointers(this, cm);
 658   }
 659   // Else skip it.  The TypeArrayKlass in the header never needs scavenging.
 660 }
 661 
 662 void oopDesc::ps_push_contents(PSPromotionManager* pm) {
 663   Klass* k = klass();
 664   if (!k->is_typeArray_klass()) {
 665     // It might contain oops beyond the header, so take the virtual call.
 666     k->oop_ps_push_contents(this, pm);
 667   }
 668   // Else skip it.  The TypeArrayKlass in the header never needs scavenging.
 669 }
 670 #endif // INCLUDE_ALL_GCS
 671 
 672 #define OOP_ITERATE_DEFN(OopClosureType, nv_suffix)                 \
 673                                                                     \
 674 void oopDesc::oop_iterate(OopClosureType* blk) {                    \
 675   klass()->oop_oop_iterate##nv_suffix(this, blk);                   \
 676 }                                                                   \
 677                                                                     \
 678 void oopDesc::oop_iterate(OopClosureType* blk, MemRegion mr) {      \
 679   klass()->oop_oop_iterate_bounded##nv_suffix(this, blk, mr);       \
 680 }
 681 
 682 #define OOP_ITERATE_SIZE_DEFN(OopClosureType, nv_suffix)            \
 683                                                                     \
 684 int oopDesc::oop_iterate_size(OopClosureType* blk) {                \
 685   Klass* k = klass();                                               \
 686   int size = size_given_klass(k);                                   \
 687   k->oop_oop_iterate##nv_suffix(this, blk);                         \
 688   return size;                                                      \
 689 }                                                                   \
 690                                                                     \
 691 int oopDesc::oop_iterate_size(OopClosureType* blk, MemRegion mr) {  \
 692   Klass* k = klass();                                               \
 693   int size = size_given_klass(k);                                   \
 694   k->oop_oop_iterate_bounded##nv_suffix(this, blk, mr);             \
 695   return size;                                                      \
 696 }
 697 
 698 int oopDesc::oop_iterate_no_header(OopClosure* blk) {
 699   // The NoHeaderExtendedOopClosure wraps the OopClosure and proxies all
 700   // the do_oop calls, but turns off all other features in ExtendedOopClosure.
 701   NoHeaderExtendedOopClosure cl(blk);
 702   return oop_iterate_size(&cl);
 703 }
 704 
 705 int oopDesc::oop_iterate_no_header(OopClosure* blk, MemRegion mr) {
 706   NoHeaderExtendedOopClosure cl(blk);
 707   return oop_iterate_size(&cl, mr);
 708 }
 709 
 710 #if INCLUDE_ALL_GCS
 711 #define OOP_ITERATE_BACKWARDS_DEFN(OopClosureType, nv_suffix)       \
 712                                                                     \
 713 inline void oopDesc::oop_iterate_backwards(OopClosureType* blk) {   \
 714   klass()->oop_oop_iterate_backwards##nv_suffix(this, blk);         \
 715 }
 716 #else
 717 #define OOP_ITERATE_BACKWARDS_DEFN(OopClosureType, nv_suffix)
 718 #endif // INCLUDE_ALL_GCS
 719 
 720 #define ALL_OOPDESC_OOP_ITERATE(OopClosureType, nv_suffix)  \
 721   OOP_ITERATE_DEFN(OopClosureType, nv_suffix)               \
 722   OOP_ITERATE_SIZE_DEFN(OopClosureType, nv_suffix)          \
 723   OOP_ITERATE_BACKWARDS_DEFN(OopClosureType, nv_suffix)
 724 
 725 ALL_OOP_OOP_ITERATE_CLOSURES_1(ALL_OOPDESC_OOP_ITERATE)
 726 ALL_OOP_OOP_ITERATE_CLOSURES_2(ALL_OOPDESC_OOP_ITERATE)
 727 
 728 intptr_t oopDesc::identity_hash() {
 729   // Fast case; if the object is unlocked and the hash value is set, no locking is needed
 730   // Note: The mark must be read into local variable to avoid concurrent updates.
 731   markOop mrk = mark();
 732   if (mrk->is_unlocked() && !mrk->has_no_hash()) {
 733     return mrk->hash();
 734   } else if (mrk->is_marked()) {
 735     return mrk->hash();
 736   } else {
 737     return slow_identity_hash();
 738   }
 739 }
 740 
 741 bool oopDesc::has_displaced_mark() const {
 742   return mark()->has_displaced_mark_helper();
 743 }
 744 
 745 markOop oopDesc::displaced_mark() const {
 746   return mark()->displaced_mark_helper();
 747 }
 748 
 749 void oopDesc::set_displaced_mark(markOop m) {
 750   mark()->set_displaced_mark_helper(m);
 751 }
 752 
 753 #endif // SHARE_VM_OOPS_OOP_INLINE_HPP