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_implementation/shared/ageTable.hpp"
  29 #include "gc_implementation/shared/markSweep.inline.hpp"
  30 #include "gc_interface/collectedHeap.inline.hpp"
  31 #include "memory/barrierSet.inline.hpp"
  32 #include "memory/cardTableModRefBS.hpp"
  33 #include "memory/genCollectedHeap.hpp"
  34 #include "memory/generation.hpp"
  35 #include "memory/specialized_oop_closures.hpp"
  36 #include "oops/arrayKlass.hpp"
  37 #include "oops/arrayOop.hpp"
  38 #include "oops/klass.inline.hpp"
  39 #include "oops/markOop.inline.hpp"
  40 #include "oops/oop.hpp"
  41 #include "runtime/atomic.inline.hpp"
  42 #include "runtime/orderAccess.inline.hpp"
  43 #include "runtime/os.hpp"
  44 #include "utilities/macros.hpp"
  45 #ifdef TARGET_ARCH_x86
  46 # include "bytes_x86.hpp"
  47 #endif
  48 #ifdef TARGET_ARCH_sparc
  49 # include "bytes_sparc.hpp"
  50 #endif
  51 #ifdef TARGET_ARCH_zero
  52 # include "bytes_zero.hpp"
  53 #endif
  54 #ifdef TARGET_ARCH_arm
  55 # include "bytes_arm.hpp"
  56 #endif
  57 #ifdef TARGET_ARCH_ppc
  58 # include "bytes_ppc.hpp"
  59 #endif
  60 #ifdef TARGET_ARCH_aarch32
  61 # include "bytes_aarch32.hpp"
  62 #endif
  63 
  64 // Implementation of all inlined member functions defined in oop.hpp
  65 // We need a separate file to avoid circular references
  66 
  67 inline void oopDesc::release_set_mark(markOop m) {
  68   OrderAccess::release_store_ptr(&_mark, m);
  69 }
  70 
  71 inline markOop oopDesc::cas_set_mark(markOop new_mark, markOop old_mark) {
  72   return (markOop) Atomic::cmpxchg_ptr(new_mark, &_mark, old_mark);
  73 }
  74 
  75 inline Klass* oopDesc::klass() const {
  76   if (UseCompressedClassPointers) {
  77     return Klass::decode_klass_not_null(_metadata._compressed_klass);
  78   } else {
  79     return _metadata._klass;
  80   }
  81 }
  82 
  83 inline Klass* oopDesc::klass_or_null() const volatile {
  84   // can be NULL in CMS
  85   if (UseCompressedClassPointers) {
  86     return Klass::decode_klass(_metadata._compressed_klass);
  87   } else {
  88     return _metadata._klass;
  89   }
  90 }
  91 
  92 inline int oopDesc::klass_gap_offset_in_bytes() {
  93   assert(UseCompressedClassPointers, "only applicable to compressed klass pointers");
  94   return oopDesc::klass_offset_in_bytes() + sizeof(narrowKlass);
  95 }
  96 
  97 inline Klass** oopDesc::klass_addr() {
  98   // Only used internally and with CMS and will not work with
  99   // UseCompressedOops
 100   assert(!UseCompressedClassPointers, "only supported with uncompressed klass pointers");
 101   return (Klass**) &_metadata._klass;
 102 }
 103 
 104 inline narrowKlass* oopDesc::compressed_klass_addr() {
 105   assert(UseCompressedClassPointers, "only called by compressed klass pointers");
 106   return &_metadata._compressed_klass;
 107 }
 108 
 109 inline void oopDesc::set_klass(Klass* k) {
 110   // since klasses are promoted no store check is needed
 111   assert(Universe::is_bootstrapping() || k != NULL, "must be a real Klass*");
 112   assert(Universe::is_bootstrapping() || k->is_klass(), "not a Klass*");
 113   if (UseCompressedClassPointers) {
 114     *compressed_klass_addr() = Klass::encode_klass_not_null(k);
 115   } else {
 116     *klass_addr() = k;
 117   }
 118 }
 119 
 120 inline int oopDesc::klass_gap() const {
 121   return *(int*)(((intptr_t)this) + klass_gap_offset_in_bytes());
 122 }
 123 
 124 inline void oopDesc::set_klass_gap(int v) {
 125   if (UseCompressedClassPointers) {
 126     *(int*)(((intptr_t)this) + klass_gap_offset_in_bytes()) = v;
 127   }
 128 }
 129 
 130 inline void oopDesc::set_klass_to_list_ptr(oop k) {
 131   // This is only to be used during GC, for from-space objects, so no
 132   // barrier is needed.
 133   if (UseCompressedClassPointers) {
 134     _metadata._compressed_klass = (narrowKlass)encode_heap_oop(k);  // may be null (parnew overflow handling)
 135   } else {
 136     _metadata._klass = (Klass*)(address)k;
 137   }
 138 }
 139 
 140 inline oop oopDesc::list_ptr_from_klass() {
 141   // This is only to be used during GC, for from-space objects.
 142   if (UseCompressedClassPointers) {
 143     return decode_heap_oop((narrowOop)_metadata._compressed_klass);
 144   } else {
 145     // Special case for GC
 146     return (oop)(address)_metadata._klass;
 147   }
 148 }
 149 
 150 inline void   oopDesc::init_mark()                 { set_mark(markOopDesc::prototype_for_object(this)); }
 151 
 152 inline bool oopDesc::is_a(Klass* k)        const { return klass()->is_subtype_of(k); }
 153 
 154 inline bool oopDesc::is_instance()            const { return klass()->oop_is_instance(); }
 155 inline bool oopDesc::is_instanceClassLoader() const { return klass()->oop_is_instanceClassLoader(); }
 156 inline bool oopDesc::is_instanceMirror()      const { return klass()->oop_is_instanceMirror(); }
 157 inline bool oopDesc::is_instanceRef()         const { return klass()->oop_is_instanceRef(); }
 158 inline bool oopDesc::is_array()               const { return klass()->oop_is_array(); }
 159 inline bool oopDesc::is_objArray()            const { return klass()->oop_is_objArray(); }
 160 inline bool oopDesc::is_typeArray()           const { return klass()->oop_is_typeArray(); }
 161 
 162 inline void*     oopDesc::field_base(int offset)        const { return (void*)&((char*)this)[offset]; }
 163 
 164 template <class T> inline T* oopDesc::obj_field_addr(int offset) const { return (T*)field_base(offset); }
 165 inline Metadata** oopDesc::metadata_field_addr(int offset) const { return (Metadata**)field_base(offset); }
 166 inline jbyte*    oopDesc::byte_field_addr(int offset)   const { return (jbyte*)   field_base(offset); }
 167 inline jchar*    oopDesc::char_field_addr(int offset)   const { return (jchar*)   field_base(offset); }
 168 inline jboolean* oopDesc::bool_field_addr(int offset)   const { return (jboolean*)field_base(offset); }
 169 inline jint*     oopDesc::int_field_addr(int offset)    const { return (jint*)    field_base(offset); }
 170 inline jshort*   oopDesc::short_field_addr(int offset)  const { return (jshort*)  field_base(offset); }
 171 inline jlong*    oopDesc::long_field_addr(int offset)   const { return (jlong*)   field_base(offset); }
 172 inline jfloat*   oopDesc::float_field_addr(int offset)  const { return (jfloat*)  field_base(offset); }
 173 inline jdouble*  oopDesc::double_field_addr(int offset) const { return (jdouble*) field_base(offset); }
 174 inline address*  oopDesc::address_field_addr(int offset) const { return (address*) field_base(offset); }
 175 
 176 
 177 // Functions for getting and setting oops within instance objects.
 178 // If the oops are compressed, the type passed to these overloaded functions
 179 // is narrowOop.  All functions are overloaded so they can be called by
 180 // template functions without conditionals (the compiler instantiates via
 181 // the right type and inlines the appopriate code).
 182 
 183 inline bool oopDesc::is_null(oop obj)       { return obj == NULL; }
 184 inline bool oopDesc::is_null(narrowOop obj) { return obj == 0; }
 185 
 186 // Algorithm for encoding and decoding oops from 64 bit pointers to 32 bit
 187 // offset from the heap base.  Saving the check for null can save instructions
 188 // in inner GC loops so these are separated.
 189 
 190 inline bool check_obj_alignment(oop obj) {
 191   return cast_from_oop<intptr_t>(obj) % MinObjAlignmentInBytes == 0;
 192 }
 193 
 194 inline narrowOop oopDesc::encode_heap_oop_not_null(oop v) {
 195   assert(!is_null(v), "oop value can never be zero");
 196   assert(check_obj_alignment(v), "Address not aligned");
 197   assert(Universe::heap()->is_in_reserved(v), "Address not in heap");
 198   address base = Universe::narrow_oop_base();
 199   int    shift = Universe::narrow_oop_shift();
 200   uint64_t  pd = (uint64_t)(pointer_delta((void*)v, (void*)base, 1));
 201   assert(OopEncodingHeapMax > pd, "change encoding max if new encoding");
 202   uint64_t result = pd >> shift;
 203   assert((result & CONST64(0xffffffff00000000)) == 0, "narrow oop overflow");
 204   assert(decode_heap_oop(result) == v, "reversibility");
 205   return (narrowOop)result;
 206 }
 207 
 208 inline narrowOop oopDesc::encode_heap_oop(oop v) {
 209   return (is_null(v)) ? (narrowOop)0 : encode_heap_oop_not_null(v);
 210 }
 211 
 212 inline oop oopDesc::decode_heap_oop_not_null(narrowOop v) {
 213   assert(!is_null(v), "narrow oop value can never be zero");
 214   address base = Universe::narrow_oop_base();
 215   int    shift = Universe::narrow_oop_shift();
 216   oop result = (oop)(void*)((uintptr_t)base + ((uintptr_t)v << shift));
 217   assert(check_obj_alignment(result), err_msg("address not aligned: " INTPTR_FORMAT, p2i((void*) result)));
 218   return result;
 219 }
 220 
 221 inline oop oopDesc::decode_heap_oop(narrowOop v) {
 222   return is_null(v) ? (oop)NULL : decode_heap_oop_not_null(v);
 223 }
 224 
 225 inline oop oopDesc::decode_heap_oop_not_null(oop v) { return v; }
 226 inline oop oopDesc::decode_heap_oop(oop v)  { return v; }
 227 
 228 // Load an oop out of the Java heap as is without decoding.
 229 // Called by GC to check for null before decoding.
 230 inline oop       oopDesc::load_heap_oop(oop* p)          { return *p; }
 231 inline narrowOop oopDesc::load_heap_oop(narrowOop* p)    { return *p; }
 232 
 233 // Load and decode an oop out of the Java heap into a wide oop.
 234 inline oop oopDesc::load_decode_heap_oop_not_null(oop* p)       { return *p; }
 235 inline oop oopDesc::load_decode_heap_oop_not_null(narrowOop* p) {
 236   return decode_heap_oop_not_null(*p);
 237 }
 238 
 239 // Load and decode an oop out of the heap accepting null
 240 inline oop oopDesc::load_decode_heap_oop(oop* p) { return *p; }
 241 inline oop oopDesc::load_decode_heap_oop(narrowOop* p) {
 242   return decode_heap_oop(*p);
 243 }
 244 
 245 // Store already encoded heap oop into the heap.
 246 inline void oopDesc::store_heap_oop(oop* p, oop v)                 { *p = v; }
 247 inline void oopDesc::store_heap_oop(narrowOop* p, narrowOop v)     { *p = v; }
 248 
 249 // Encode and store a heap oop.
 250 inline void oopDesc::encode_store_heap_oop_not_null(narrowOop* p, oop v) {
 251   *p = encode_heap_oop_not_null(v);
 252 }
 253 inline void oopDesc::encode_store_heap_oop_not_null(oop* p, oop v) { *p = v; }
 254 
 255 // Encode and store a heap oop allowing for null.
 256 inline void oopDesc::encode_store_heap_oop(narrowOop* p, oop v) {
 257   *p = encode_heap_oop(v);
 258 }
 259 inline void oopDesc::encode_store_heap_oop(oop* p, oop v) { *p = v; }
 260 
 261 // Store heap oop as is for volatile fields.
 262 inline void oopDesc::release_store_heap_oop(volatile oop* p, oop v) {
 263   OrderAccess::release_store_ptr(p, v);
 264 }
 265 inline void oopDesc::release_store_heap_oop(volatile narrowOop* p,
 266                                             narrowOop v) {
 267   OrderAccess::release_store(p, v);
 268 }
 269 
 270 inline void oopDesc::release_encode_store_heap_oop_not_null(
 271                                                 volatile narrowOop* p, oop v) {
 272   // heap oop is not pointer sized.
 273   OrderAccess::release_store(p, encode_heap_oop_not_null(v));
 274 }
 275 
 276 inline void oopDesc::release_encode_store_heap_oop_not_null(
 277                                                       volatile oop* p, oop v) {
 278   OrderAccess::release_store_ptr(p, v);
 279 }
 280 
 281 inline void oopDesc::release_encode_store_heap_oop(volatile oop* p,
 282                                                            oop v) {
 283   OrderAccess::release_store_ptr(p, v);
 284 }
 285 inline void oopDesc::release_encode_store_heap_oop(
 286                                                 volatile narrowOop* p, oop v) {
 287   OrderAccess::release_store(p, encode_heap_oop(v));
 288 }
 289 
 290 
 291 // These functions are only used to exchange oop fields in instances,
 292 // not headers.
 293 inline oop oopDesc::atomic_exchange_oop(oop exchange_value, volatile HeapWord *dest) {
 294   if (UseCompressedOops) {
 295     // encode exchange value from oop to T
 296     narrowOop val = encode_heap_oop(exchange_value);
 297     narrowOop old = (narrowOop)Atomic::xchg(val, (narrowOop*)dest);
 298     // decode old from T to oop
 299     return decode_heap_oop(old);
 300   } else {
 301     return (oop)Atomic::xchg_ptr(exchange_value, (oop*)dest);
 302   }
 303 }
 304 
 305 // In order to put or get a field out of an instance, must first check
 306 // if the field has been compressed and uncompress it.
 307 inline oop oopDesc::obj_field(int offset) const {
 308   return UseCompressedOops ?
 309     load_decode_heap_oop(obj_field_addr<narrowOop>(offset)) :
 310     load_decode_heap_oop(obj_field_addr<oop>(offset));
 311 }
 312 inline volatile oop oopDesc::obj_field_volatile(int offset) const {
 313   volatile oop value = obj_field(offset);
 314   OrderAccess::acquire();
 315   return value;
 316 }
 317 inline void oopDesc::obj_field_put(int offset, oop value) {
 318   UseCompressedOops ? oop_store(obj_field_addr<narrowOop>(offset), value) :
 319                       oop_store(obj_field_addr<oop>(offset),       value);
 320 }
 321 
 322 inline Metadata* oopDesc::metadata_field(int offset) const {
 323   return *metadata_field_addr(offset);
 324 }
 325 
 326 inline void oopDesc::metadata_field_put(int offset, Metadata* value) {
 327   *metadata_field_addr(offset) = value;
 328 }
 329 
 330 inline void oopDesc::obj_field_put_raw(int offset, oop value) {
 331   UseCompressedOops ?
 332     encode_store_heap_oop(obj_field_addr<narrowOop>(offset), value) :
 333     encode_store_heap_oop(obj_field_addr<oop>(offset),       value);
 334 }
 335 inline void oopDesc::obj_field_put_volatile(int offset, oop value) {
 336   OrderAccess::release();
 337   obj_field_put(offset, value);
 338   OrderAccess::fence();
 339 }
 340 
 341 inline jbyte oopDesc::byte_field(int offset) const                  { return (jbyte) *byte_field_addr(offset);    }
 342 inline void oopDesc::byte_field_put(int offset, jbyte contents)     { *byte_field_addr(offset) = (jint) contents; }
 343 
 344 inline jboolean oopDesc::bool_field(int offset) const               { return (jboolean) *bool_field_addr(offset); }
 345 inline void oopDesc::bool_field_put(int offset, jboolean contents)  { *bool_field_addr(offset) = (( (jint) contents) & 1); }
 346 
 347 inline jchar oopDesc::char_field(int offset) const                  { return (jchar) *char_field_addr(offset);    }
 348 inline void oopDesc::char_field_put(int offset, jchar contents)     { *char_field_addr(offset) = (jint) contents; }
 349 
 350 inline jint oopDesc::int_field(int offset) const                    { return *int_field_addr(offset);        }
 351 inline void oopDesc::int_field_put(int offset, jint contents)       { *int_field_addr(offset) = contents;    }
 352 
 353 inline jshort oopDesc::short_field(int offset) const                { return (jshort) *short_field_addr(offset);  }
 354 inline void oopDesc::short_field_put(int offset, jshort contents)   { *short_field_addr(offset) = (jint) contents;}
 355 
 356 inline jlong oopDesc::long_field(int offset) const                  { return *long_field_addr(offset);       }
 357 inline void oopDesc::long_field_put(int offset, jlong contents)     { *long_field_addr(offset) = contents;   }
 358 
 359 inline jfloat oopDesc::float_field(int offset) const                { return *float_field_addr(offset);      }
 360 inline void oopDesc::float_field_put(int offset, jfloat contents)   { *float_field_addr(offset) = contents;  }
 361 
 362 inline jdouble oopDesc::double_field(int offset) const              { return *double_field_addr(offset);     }
 363 inline void oopDesc::double_field_put(int offset, jdouble contents) { *double_field_addr(offset) = contents; }
 364 
 365 inline address oopDesc::address_field(int offset) const              { return *address_field_addr(offset);     }
 366 inline void oopDesc::address_field_put(int offset, address contents) { *address_field_addr(offset) = contents; }
 367 
 368 inline oop oopDesc::obj_field_acquire(int offset) const {
 369   return UseCompressedOops ?
 370              decode_heap_oop((narrowOop)
 371                OrderAccess::load_acquire(obj_field_addr<narrowOop>(offset)))
 372            : decode_heap_oop((oop)
 373                OrderAccess::load_ptr_acquire(obj_field_addr<oop>(offset)));
 374 }
 375 inline void oopDesc::release_obj_field_put(int offset, oop value) {
 376   UseCompressedOops ?
 377     oop_store((volatile narrowOop*)obj_field_addr<narrowOop>(offset), value) :
 378     oop_store((volatile oop*)      obj_field_addr<oop>(offset),       value);
 379 }
 380 
 381 inline jbyte oopDesc::byte_field_acquire(int offset) const                  { return OrderAccess::load_acquire(byte_field_addr(offset));     }
 382 inline void oopDesc::release_byte_field_put(int offset, jbyte contents)     { OrderAccess::release_store(byte_field_addr(offset), contents); }
 383 
 384 inline jboolean oopDesc::bool_field_acquire(int offset) const               { return OrderAccess::load_acquire(bool_field_addr(offset));     }
 385 inline void oopDesc::release_bool_field_put(int offset, jboolean contents)  { OrderAccess::release_store(bool_field_addr(offset), (contents & 1)); }
 386 
 387 inline jchar oopDesc::char_field_acquire(int offset) const                  { return OrderAccess::load_acquire(char_field_addr(offset));     }
 388 inline void oopDesc::release_char_field_put(int offset, jchar contents)     { OrderAccess::release_store(char_field_addr(offset), contents); }
 389 
 390 inline jint oopDesc::int_field_acquire(int offset) const                    { return OrderAccess::load_acquire(int_field_addr(offset));      }
 391 inline void oopDesc::release_int_field_put(int offset, jint contents)       { OrderAccess::release_store(int_field_addr(offset), contents);  }
 392 
 393 inline jshort oopDesc::short_field_acquire(int offset) const                { return (jshort)OrderAccess::load_acquire(short_field_addr(offset)); }
 394 inline void oopDesc::release_short_field_put(int offset, jshort contents)   { OrderAccess::release_store(short_field_addr(offset), contents);     }
 395 
 396 inline jlong oopDesc::long_field_acquire(int offset) const                  { return OrderAccess::load_acquire(long_field_addr(offset));       }
 397 inline void oopDesc::release_long_field_put(int offset, jlong contents)     { OrderAccess::release_store(long_field_addr(offset), contents);   }
 398 
 399 inline jfloat oopDesc::float_field_acquire(int offset) const                { return OrderAccess::load_acquire(float_field_addr(offset));      }
 400 inline void oopDesc::release_float_field_put(int offset, jfloat contents)   { OrderAccess::release_store(float_field_addr(offset), contents);  }
 401 
 402 inline jdouble oopDesc::double_field_acquire(int offset) const              { return OrderAccess::load_acquire(double_field_addr(offset));     }
 403 inline void oopDesc::release_double_field_put(int offset, jdouble contents) { OrderAccess::release_store(double_field_addr(offset), contents); }
 404 
 405 inline address oopDesc::address_field_acquire(int offset) const             { return (address) OrderAccess::load_ptr_acquire(address_field_addr(offset)); }
 406 inline void oopDesc::release_address_field_put(int offset, address contents) { OrderAccess::release_store_ptr(address_field_addr(offset), contents); }
 407 
 408 inline int oopDesc::size_given_klass(Klass* klass)  {
 409   int lh = klass->layout_helper();
 410   int s;
 411 
 412   // lh is now a value computed at class initialization that may hint
 413   // at the size.  For instances, this is positive and equal to the
 414   // size.  For arrays, this is negative and provides log2 of the
 415   // array element size.  For other oops, it is zero and thus requires
 416   // a virtual call.
 417   //
 418   // We go to all this trouble because the size computation is at the
 419   // heart of phase 2 of mark-compaction, and called for every object,
 420   // alive or dead.  So the speed here is equal in importance to the
 421   // speed of allocation.
 422 
 423   if (lh > Klass::_lh_neutral_value) {
 424     if (!Klass::layout_helper_needs_slow_path(lh)) {
 425       s = lh >> LogHeapWordSize;  // deliver size scaled by wordSize
 426     } else {
 427       s = klass->oop_size(this);
 428     }
 429   } else if (lh <= Klass::_lh_neutral_value) {
 430     // The most common case is instances; fall through if so.
 431     if (lh < Klass::_lh_neutral_value) {
 432       // Second most common case is arrays.  We have to fetch the
 433       // length of the array, shift (multiply) it appropriately,
 434       // up to wordSize, add the header, and align to object size.
 435       size_t size_in_bytes;
 436 #ifdef _M_IA64
 437       // The Windows Itanium Aug 2002 SDK hoists this load above
 438       // the check for s < 0.  An oop at the end of the heap will
 439       // cause an access violation if this load is performed on a non
 440       // array oop.  Making the reference volatile prohibits this.
 441       // (%%% please explain by what magic the length is actually fetched!)
 442       volatile int *array_length;
 443       array_length = (volatile int *)( (intptr_t)this +
 444                           arrayOopDesc::length_offset_in_bytes() );
 445       assert(array_length > 0, "Integer arithmetic problem somewhere");
 446       // Put into size_t to avoid overflow.
 447       size_in_bytes = (size_t) array_length;
 448       size_in_bytes = size_in_bytes << Klass::layout_helper_log2_element_size(lh);
 449 #else
 450       size_t array_length = (size_t) ((arrayOop)this)->length();
 451       size_in_bytes = array_length << Klass::layout_helper_log2_element_size(lh);
 452 #endif
 453       size_in_bytes += Klass::layout_helper_header_size(lh);
 454 
 455       // This code could be simplified, but by keeping array_header_in_bytes
 456       // in units of bytes and doing it this way we can round up just once,
 457       // skipping the intermediate round to HeapWordSize.  Cast the result
 458       // of round_to to size_t to guarantee unsigned division == right shift.
 459       s = (int)((size_t)round_to(size_in_bytes, MinObjAlignmentInBytes) /
 460         HeapWordSize);
 461 
 462       // UseParNewGC, UseParallelGC and UseG1GC can change the length field
 463       // of an "old copy" of an object array in the young gen so it indicates
 464       // the grey portion of an already copied array. This will cause the first
 465       // disjunct below to fail if the two comparands are computed across such
 466       // a concurrent change.
 467       // UseParNewGC also runs with promotion labs (which look like int
 468       // filler arrays) which are subject to changing their declared size
 469       // when finally retiring a PLAB; this also can cause the first disjunct
 470       // to fail for another worker thread that is concurrently walking the block
 471       // offset table. Both these invariant failures are benign for their
 472       // current uses; we relax the assertion checking to cover these two cases below:
 473       //     is_objArray() && is_forwarded()   // covers first scenario above
 474       //  || is_typeArray()                    // covers second scenario above
 475       // If and when UseParallelGC uses the same obj array oop stealing/chunking
 476       // technique, we will need to suitably modify the assertion.
 477       assert((s == klass->oop_size(this)) ||
 478              (Universe::heap()->is_gc_active() &&
 479               ((is_typeArray() && UseParNewGC) ||
 480                (is_objArray()  && is_forwarded() && (UseParNewGC || UseParallelGC || UseG1GC)))),
 481              "wrong array object size");
 482     } else {
 483       // Must be zero, so bite the bullet and take the virtual call.
 484       s = klass->oop_size(this);
 485     }
 486   }
 487 
 488   assert(s % MinObjAlignment == 0, "alignment check");
 489   assert(s > 0, "Bad size calculated");
 490   return s;
 491 }
 492 
 493 
 494 inline int oopDesc::size()  {
 495   return size_given_klass(klass());
 496 }
 497 
 498 inline void update_barrier_set(void* p, oop v, bool release = false) {
 499   assert(oopDesc::bs() != NULL, "Uninitialized bs in oop!");
 500   oopDesc::bs()->write_ref_field(p, v, release);
 501 }
 502 
 503 template <class T> inline void update_barrier_set_pre(T* p, oop v) {
 504   oopDesc::bs()->write_ref_field_pre(p, v);
 505 }
 506 
 507 template <class T> inline void oop_store(T* p, oop v) {
 508   if (always_do_update_barrier) {
 509     oop_store((volatile T*)p, v);
 510   } else {
 511     update_barrier_set_pre(p, v);
 512     oopDesc::encode_store_heap_oop(p, v);
 513     // always_do_update_barrier == false =>
 514     // Either we are at a safepoint (in GC) or CMS is not used. In both
 515     // cases it's unnecessary to mark the card as dirty with release sematics.
 516     update_barrier_set((void*)p, v, false /* release */);  // cast away type
 517   }
 518 }
 519 
 520 template <class T> inline void oop_store(volatile T* p, oop v) {
 521   update_barrier_set_pre((T*)p, v);   // cast away volatile
 522   // Used by release_obj_field_put, so use release_store_ptr.
 523   oopDesc::release_encode_store_heap_oop(p, v);
 524   // When using CMS we must mark the card corresponding to p as dirty
 525   // with release sematics to prevent that CMS sees the dirty card but
 526   // not the new value v at p due to reordering of the two
 527   // stores. Note that CMS has a concurrent precleaning phase, where
 528   // it reads the card table while the Java threads are running.
 529   update_barrier_set((void*)p, v, true /* release */);    // cast away type
 530 }
 531 
 532 // Should replace *addr = oop assignments where addr type depends on UseCompressedOops
 533 // (without having to remember the function name this calls).
 534 inline void oop_store_raw(HeapWord* addr, oop value) {
 535   if (UseCompressedOops) {
 536     oopDesc::encode_store_heap_oop((narrowOop*)addr, value);
 537   } else {
 538     oopDesc::encode_store_heap_oop((oop*)addr, value);
 539   }
 540 }
 541 
 542 inline oop oopDesc::atomic_compare_exchange_oop(oop exchange_value,
 543                                                 volatile HeapWord *dest,
 544                                                 oop compare_value,
 545                                                 bool prebarrier) {
 546   if (UseCompressedOops) {
 547     if (prebarrier) {
 548       update_barrier_set_pre((narrowOop*)dest, exchange_value);
 549     }
 550     // encode exchange and compare value from oop to T
 551     narrowOop val = encode_heap_oop(exchange_value);
 552     narrowOop cmp = encode_heap_oop(compare_value);
 553 
 554     narrowOop old = (narrowOop) Atomic::cmpxchg(val, (narrowOop*)dest, cmp);
 555     // decode old from T to oop
 556     return decode_heap_oop(old);
 557   } else {
 558     if (prebarrier) {
 559       update_barrier_set_pre((oop*)dest, exchange_value);
 560     }
 561     return (oop)Atomic::cmpxchg_ptr(exchange_value, (oop*)dest, compare_value);
 562   }
 563 }
 564 
 565 // Used only for markSweep, scavenging
 566 inline bool oopDesc::is_gc_marked() const {
 567   return mark()->is_marked();
 568 }
 569 
 570 inline bool oopDesc::is_locked() const {
 571   return mark()->is_locked();
 572 }
 573 
 574 inline bool oopDesc::is_unlocked() const {
 575   return mark()->is_unlocked();
 576 }
 577 
 578 inline bool oopDesc::has_bias_pattern() const {
 579   return mark()->has_bias_pattern();
 580 }
 581 
 582 
 583 // used only for asserts
 584 inline bool oopDesc::is_oop(bool ignore_mark_word) const {
 585   oop obj = (oop) this;
 586   if (!check_obj_alignment(obj)) return false;
 587   if (!Universe::heap()->is_in_reserved(obj)) return false;
 588   // obj is aligned and accessible in heap
 589   if (Universe::heap()->is_in_reserved(obj->klass_or_null())) return false;
 590 
 591   // Header verification: the mark is typically non-NULL. If we're
 592   // at a safepoint, it must not be null.
 593   // Outside of a safepoint, the header could be changing (for example,
 594   // another thread could be inflating a lock on this object).
 595   if (ignore_mark_word) {
 596     return true;
 597   }
 598   if (mark() != NULL) {
 599     return true;
 600   }
 601   return !SafepointSynchronize::is_at_safepoint();
 602 }
 603 
 604 
 605 // used only for asserts
 606 inline bool oopDesc::is_oop_or_null(bool ignore_mark_word) const {
 607   return this == NULL ? true : is_oop(ignore_mark_word);
 608 }
 609 
 610 #ifndef PRODUCT
 611 // used only for asserts
 612 inline bool oopDesc::is_unlocked_oop() const {
 613   if (!Universe::heap()->is_in_reserved(this)) return false;
 614   return mark()->is_unlocked();
 615 }
 616 #endif // PRODUCT
 617 
 618 inline void oopDesc::follow_contents(void) {
 619   assert (is_gc_marked(), "should be marked");
 620   klass()->oop_follow_contents(this);
 621 }
 622 
 623 // Used by scavengers
 624 
 625 inline bool oopDesc::is_forwarded() const {
 626   // The extra heap check is needed since the obj might be locked, in which case the
 627   // mark would point to a stack location and have the sentinel bit cleared
 628   return mark()->is_marked();
 629 }
 630 
 631 // Used by scavengers
 632 inline void oopDesc::forward_to(oop p) {
 633   assert(check_obj_alignment(p),
 634          "forwarding to something not aligned");
 635   assert(Universe::heap()->is_in_reserved(p),
 636          "forwarding to something not in heap");
 637   markOop m = markOopDesc::encode_pointer_as_mark(p);
 638   assert(m->decode_pointer() == p, "encoding must be reversable");
 639   set_mark(m);
 640 }
 641 
 642 // Used by parallel scavengers
 643 inline bool oopDesc::cas_forward_to(oop p, markOop compare) {
 644   assert(check_obj_alignment(p),
 645          "forwarding to something not aligned");
 646   assert(Universe::heap()->is_in_reserved(p),
 647          "forwarding to something not in heap");
 648   markOop m = markOopDesc::encode_pointer_as_mark(p);
 649   assert(m->decode_pointer() == p, "encoding must be reversable");
 650   return cas_set_mark(m, compare) == compare;
 651 }
 652 
 653 // Note that the forwardee is not the same thing as the displaced_mark.
 654 // The forwardee is used when copying during scavenge and mark-sweep.
 655 // It does need to clear the low two locking- and GC-related bits.
 656 inline oop oopDesc::forwardee() const {
 657   return (oop) mark()->decode_pointer();
 658 }
 659 
 660 inline bool oopDesc::has_displaced_mark() const {
 661   return mark()->has_displaced_mark_helper();
 662 }
 663 
 664 inline markOop oopDesc::displaced_mark() const {
 665   return mark()->displaced_mark_helper();
 666 }
 667 
 668 inline void oopDesc::set_displaced_mark(markOop m) {
 669   mark()->set_displaced_mark_helper(m);
 670 }
 671 
 672 // The following method needs to be MT safe.
 673 inline uint oopDesc::age() const {
 674   assert(!is_forwarded(), "Attempt to read age from forwarded mark");
 675   if (has_displaced_mark()) {
 676     return displaced_mark()->age();
 677   } else {
 678     return mark()->age();
 679   }
 680 }
 681 
 682 inline void oopDesc::incr_age() {
 683   assert(!is_forwarded(), "Attempt to increment age of forwarded mark");
 684   if (has_displaced_mark()) {
 685     set_displaced_mark(displaced_mark()->incr_age());
 686   } else {
 687     set_mark(mark()->incr_age());
 688   }
 689 }
 690 
 691 
 692 inline intptr_t oopDesc::identity_hash() {
 693   // Fast case; if the object is unlocked and the hash value is set, no locking is needed
 694   // Note: The mark must be read into local variable to avoid concurrent updates.
 695   markOop mrk = mark();
 696   if (mrk->is_unlocked() && !mrk->has_no_hash()) {
 697     return mrk->hash();
 698   } else if (mrk->is_marked()) {
 699     return mrk->hash();
 700   } else {
 701     return slow_identity_hash();
 702   }
 703 }
 704 
 705 inline int oopDesc::adjust_pointers() {
 706   debug_only(int check_size = size());
 707   int s = klass()->oop_adjust_pointers(this);
 708   assert(s == check_size, "should be the same");
 709   return s;
 710 }
 711 
 712 #define OOP_ITERATE_DEFN(OopClosureType, nv_suffix)                        \
 713                                                                            \
 714 inline int oopDesc::oop_iterate(OopClosureType* blk) {                     \
 715   SpecializationStats::record_call();                                      \
 716   return klass()->oop_oop_iterate##nv_suffix(this, blk);               \
 717 }                                                                          \
 718                                                                            \
 719 inline int oopDesc::oop_iterate(OopClosureType* blk, MemRegion mr) {       \
 720   SpecializationStats::record_call();                                      \
 721   return klass()->oop_oop_iterate##nv_suffix##_m(this, blk, mr);       \
 722 }
 723 
 724 
 725 inline int oopDesc::oop_iterate_no_header(OopClosure* blk) {
 726   // The NoHeaderExtendedOopClosure wraps the OopClosure and proxies all
 727   // the do_oop calls, but turns off all other features in ExtendedOopClosure.
 728   NoHeaderExtendedOopClosure cl(blk);
 729   return oop_iterate(&cl);
 730 }
 731 
 732 inline int oopDesc::oop_iterate_no_header(OopClosure* blk, MemRegion mr) {
 733   NoHeaderExtendedOopClosure cl(blk);
 734   return oop_iterate(&cl, mr);
 735 }
 736 
 737 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_DEFN)
 738 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_DEFN)
 739 
 740 #if INCLUDE_ALL_GCS
 741 #define OOP_ITERATE_BACKWARDS_DEFN(OopClosureType, nv_suffix)              \
 742                                                                            \
 743 inline int oopDesc::oop_iterate_backwards(OopClosureType* blk) {           \
 744   SpecializationStats::record_call();                                      \
 745   return klass()->oop_oop_iterate_backwards##nv_suffix(this, blk);     \
 746 }
 747 
 748 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_BACKWARDS_DEFN)
 749 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_BACKWARDS_DEFN)
 750 #endif // INCLUDE_ALL_GCS
 751 
 752 #endif // SHARE_VM_OOPS_OOP_INLINE_HPP