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