src/share/vm/oops/oop.inline.hpp

Tue, 08 Aug 2017 15:57:29 +0800

author
aoqi
date
Tue, 08 Aug 2017 15:57:29 +0800
changeset 6876
710a3c8b516e
parent 6680
78bbf4d43a14
parent 1
2d8a650513c2
child 7535
7ae4e26cb1e0
permissions
-rw-r--r--

merge

     1 /*
     2  * Copyright (c) 1997, 2014, 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  */
    25 /*
    26  * This file has been modified by Loongson Technology in 2015. These
    27  * modifications are Copyright (c) 2015 Loongson Technology, and are made
    28  * available on the same license terms set forth above.
    29  */
    31 #ifndef SHARE_VM_OOPS_OOP_INLINE_HPP
    32 #define SHARE_VM_OOPS_OOP_INLINE_HPP
    34 #include "gc_implementation/shared/ageTable.hpp"
    35 #include "gc_implementation/shared/markSweep.inline.hpp"
    36 #include "gc_interface/collectedHeap.inline.hpp"
    37 #include "memory/barrierSet.inline.hpp"
    38 #include "memory/cardTableModRefBS.hpp"
    39 #include "memory/genCollectedHeap.hpp"
    40 #include "memory/generation.hpp"
    41 #include "memory/specialized_oop_closures.hpp"
    42 #include "oops/arrayKlass.hpp"
    43 #include "oops/arrayOop.hpp"
    44 #include "oops/klass.inline.hpp"
    45 #include "oops/markOop.inline.hpp"
    46 #include "oops/oop.hpp"
    47 #include "runtime/atomic.hpp"
    48 #include "runtime/os.hpp"
    49 #include "utilities/macros.hpp"
    50 #ifdef TARGET_ARCH_x86
    51 # include "bytes_x86.hpp"
    52 #endif
    53 #ifdef TARGET_ARCH_sparc
    54 # include "bytes_sparc.hpp"
    55 #endif
    56 #ifdef TARGET_ARCH_zero
    57 # include "bytes_zero.hpp"
    58 #endif
    59 #ifdef TARGET_ARCH_arm
    60 # include "bytes_arm.hpp"
    61 #endif
    62 #ifdef TARGET_ARCH_ppc
    63 # include "bytes_ppc.hpp"
    64 #endif
    65 #ifdef TARGET_ARCH_mips
    66 # include "bytes_mips.hpp"
    67 #endif
    69 // Implementation of all inlined member functions defined in oop.hpp
    70 // We need a separate file to avoid circular references
    72 inline void oopDesc::release_set_mark(markOop m) {
    73   OrderAccess::release_store_ptr(&_mark, m);
    74 }
    76 inline markOop oopDesc::cas_set_mark(markOop new_mark, markOop old_mark) {
    77   return (markOop) Atomic::cmpxchg_ptr(new_mark, &_mark, old_mark);
    78 }
    80 inline Klass* oopDesc::klass() const {
    81   if (UseCompressedClassPointers) {
    82     return Klass::decode_klass_not_null(_metadata._compressed_klass);
    83   } else {
    84     return _metadata._klass;
    85   }
    86 }
    88 inline Klass* oopDesc::klass_or_null() const volatile {
    89   // can be NULL in CMS
    90   if (UseCompressedClassPointers) {
    91     return Klass::decode_klass(_metadata._compressed_klass);
    92   } else {
    93     return _metadata._klass;
    94   }
    95 }
    97 inline int oopDesc::klass_gap_offset_in_bytes() {
    98   assert(UseCompressedClassPointers, "only applicable to compressed klass pointers");
    99   return oopDesc::klass_offset_in_bytes() + sizeof(narrowKlass);
   100 }
   102 inline Klass** oopDesc::klass_addr() {
   103   // Only used internally and with CMS and will not work with
   104   // UseCompressedOops
   105   assert(!UseCompressedClassPointers, "only supported with uncompressed klass pointers");
   106   return (Klass**) &_metadata._klass;
   107 }
   109 inline narrowKlass* oopDesc::compressed_klass_addr() {
   110   assert(UseCompressedClassPointers, "only called by compressed klass pointers");
   111   return &_metadata._compressed_klass;
   112 }
   114 inline void oopDesc::set_klass(Klass* k) {
   115   // since klasses are promoted no store check is needed
   116   assert(Universe::is_bootstrapping() || k != NULL, "must be a real Klass*");
   117   assert(Universe::is_bootstrapping() || k->is_klass(), "not a Klass*");
   118   if (UseCompressedClassPointers) {
   119     *compressed_klass_addr() = Klass::encode_klass_not_null(k);
   120   } else {
   121     *klass_addr() = k;
   122   }
   123 }
   125 inline int oopDesc::klass_gap() const {
   126   return *(int*)(((intptr_t)this) + klass_gap_offset_in_bytes());
   127 }
   129 inline void oopDesc::set_klass_gap(int v) {
   130   if (UseCompressedClassPointers) {
   131     *(int*)(((intptr_t)this) + klass_gap_offset_in_bytes()) = v;
   132   }
   133 }
   135 inline void oopDesc::set_klass_to_list_ptr(oop k) {
   136   // This is only to be used during GC, for from-space objects, so no
   137   // barrier is needed.
   138   if (UseCompressedClassPointers) {
   139     _metadata._compressed_klass = (narrowKlass)encode_heap_oop(k);  // may be null (parnew overflow handling)
   140   } else {
   141     _metadata._klass = (Klass*)(address)k;
   142   }
   143 }
   145 inline oop oopDesc::list_ptr_from_klass() {
   146   // This is only to be used during GC, for from-space objects.
   147   if (UseCompressedClassPointers) {
   148     return decode_heap_oop((narrowOop)_metadata._compressed_klass);
   149   } else {
   150     // Special case for GC
   151     return (oop)(address)_metadata._klass;
   152   }
   153 }
   155 inline void   oopDesc::init_mark()                 { set_mark(markOopDesc::prototype_for_object(this)); }
   157 inline bool oopDesc::is_a(Klass* k)        const { return klass()->is_subtype_of(k); }
   159 inline bool oopDesc::is_instance()           const { return klass()->oop_is_instance(); }
   160 inline bool oopDesc::is_instanceMirror()     const { return klass()->oop_is_instanceMirror(); }
   161 inline bool oopDesc::is_instanceRef()        const { return klass()->oop_is_instanceRef(); }
   162 inline bool oopDesc::is_array()              const { return klass()->oop_is_array(); }
   163 inline bool oopDesc::is_objArray()           const { return klass()->oop_is_objArray(); }
   164 inline bool oopDesc::is_typeArray()          const { return klass()->oop_is_typeArray(); }
   166 inline void*     oopDesc::field_base(int offset)        const { return (void*)&((char*)this)[offset]; }
   168 template <class T> inline T* oopDesc::obj_field_addr(int offset) const { return (T*)field_base(offset); }
   169 inline Metadata** oopDesc::metadata_field_addr(int offset) const { return (Metadata**)field_base(offset); }
   170 inline jbyte*    oopDesc::byte_field_addr(int offset)   const { return (jbyte*)   field_base(offset); }
   171 inline jchar*    oopDesc::char_field_addr(int offset)   const { return (jchar*)   field_base(offset); }
   172 inline jboolean* oopDesc::bool_field_addr(int offset)   const { return (jboolean*)field_base(offset); }
   173 inline jint*     oopDesc::int_field_addr(int offset)    const { return (jint*)    field_base(offset); }
   174 inline jshort*   oopDesc::short_field_addr(int offset)  const { return (jshort*)  field_base(offset); }
   175 inline jlong*    oopDesc::long_field_addr(int offset)   const { return (jlong*)   field_base(offset); }
   176 inline jfloat*   oopDesc::float_field_addr(int offset)  const { return (jfloat*)  field_base(offset); }
   177 inline jdouble*  oopDesc::double_field_addr(int offset) const { return (jdouble*) field_base(offset); }
   178 inline address*  oopDesc::address_field_addr(int offset) const { return (address*) field_base(offset); }
   181 // Functions for getting and setting oops within instance objects.
   182 // If the oops are compressed, the type passed to these overloaded functions
   183 // is narrowOop.  All functions are overloaded so they can be called by
   184 // template functions without conditionals (the compiler instantiates via
   185 // the right type and inlines the appopriate code).
   187 inline bool oopDesc::is_null(oop obj)       { return obj == NULL; }
   188 inline bool oopDesc::is_null(narrowOop obj) { return obj == 0; }
   190 // Algorithm for encoding and decoding oops from 64 bit pointers to 32 bit
   191 // offset from the heap base.  Saving the check for null can save instructions
   192 // in inner GC loops so these are separated.
   194 inline bool check_obj_alignment(oop obj) {
   195   return cast_from_oop<intptr_t>(obj) % MinObjAlignmentInBytes == 0;
   196 }
   198 inline narrowOop oopDesc::encode_heap_oop_not_null(oop v) {
   199   assert(!is_null(v), "oop value can never be zero");
   200   assert(check_obj_alignment(v), "Address not aligned");
   201   assert(Universe::heap()->is_in_reserved(v), "Address not in heap");
   202   address base = Universe::narrow_oop_base();
   203   int    shift = Universe::narrow_oop_shift();
   204   uint64_t  pd = (uint64_t)(pointer_delta((void*)v, (void*)base, 1));
   205   assert(OopEncodingHeapMax > pd, "change encoding max if new encoding");
   206   uint64_t result = pd >> shift;
   207   assert((result & CONST64(0xffffffff00000000)) == 0, "narrow oop overflow");
   208   assert(decode_heap_oop(result) == v, "reversibility");
   209   return (narrowOop)result;
   210 }
   212 inline narrowOop oopDesc::encode_heap_oop(oop v) {
   213   return (is_null(v)) ? (narrowOop)0 : encode_heap_oop_not_null(v);
   214 }
   216 inline oop oopDesc::decode_heap_oop_not_null(narrowOop v) {
   217   assert(!is_null(v), "narrow oop value can never be zero");
   218   address base = Universe::narrow_oop_base();
   219   int    shift = Universe::narrow_oop_shift();
   220   oop result = (oop)(void*)((uintptr_t)base + ((uintptr_t)v << shift));
   221   assert(check_obj_alignment(result), err_msg("address not aligned: " INTPTR_FORMAT, p2i((void*) result)));
   222   return result;
   223 }
   225 inline oop oopDesc::decode_heap_oop(narrowOop v) {
   226   return is_null(v) ? (oop)NULL : decode_heap_oop_not_null(v);
   227 }
   229 inline oop oopDesc::decode_heap_oop_not_null(oop v) { return v; }
   230 inline oop oopDesc::decode_heap_oop(oop v)  { return v; }
   232 // Load an oop out of the Java heap as is without decoding.
   233 // Called by GC to check for null before decoding.
   234 inline oop       oopDesc::load_heap_oop(oop* p)          { return *p; }
   235 inline narrowOop oopDesc::load_heap_oop(narrowOop* p)    { return *p; }
   237 // Load and decode an oop out of the Java heap into a wide oop.
   238 inline oop oopDesc::load_decode_heap_oop_not_null(oop* p)       { return *p; }
   239 inline oop oopDesc::load_decode_heap_oop_not_null(narrowOop* p) {
   240   return decode_heap_oop_not_null(*p);
   241 }
   243 // Load and decode an oop out of the heap accepting null
   244 inline oop oopDesc::load_decode_heap_oop(oop* p) { return *p; }
   245 inline oop oopDesc::load_decode_heap_oop(narrowOop* p) {
   246   return decode_heap_oop(*p);
   247 }
   249 // Store already encoded heap oop into the heap.
   250 inline void oopDesc::store_heap_oop(oop* p, oop v)                 { *p = v; }
   251 inline void oopDesc::store_heap_oop(narrowOop* p, narrowOop v)     { *p = v; }
   253 // Encode and store a heap oop.
   254 inline void oopDesc::encode_store_heap_oop_not_null(narrowOop* p, oop v) {
   255   *p = encode_heap_oop_not_null(v);
   256 }
   257 inline void oopDesc::encode_store_heap_oop_not_null(oop* p, oop v) { *p = v; }
   259 // Encode and store a heap oop allowing for null.
   260 inline void oopDesc::encode_store_heap_oop(narrowOop* p, oop v) {
   261   *p = encode_heap_oop(v);
   262 }
   263 inline void oopDesc::encode_store_heap_oop(oop* p, oop v) { *p = v; }
   265 // Store heap oop as is for volatile fields.
   266 inline void oopDesc::release_store_heap_oop(volatile oop* p, oop v) {
   267   OrderAccess::release_store_ptr(p, v);
   268 }
   269 inline void oopDesc::release_store_heap_oop(volatile narrowOop* p,
   270                                             narrowOop v) {
   271   OrderAccess::release_store(p, v);
   272 }
   274 inline void oopDesc::release_encode_store_heap_oop_not_null(
   275                                                 volatile narrowOop* p, oop v) {
   276   // heap oop is not pointer sized.
   277   OrderAccess::release_store(p, encode_heap_oop_not_null(v));
   278 }
   280 inline void oopDesc::release_encode_store_heap_oop_not_null(
   281                                                       volatile oop* p, oop v) {
   282   OrderAccess::release_store_ptr(p, v);
   283 }
   285 inline void oopDesc::release_encode_store_heap_oop(volatile oop* p,
   286                                                            oop v) {
   287   OrderAccess::release_store_ptr(p, v);
   288 }
   289 inline void oopDesc::release_encode_store_heap_oop(
   290                                                 volatile narrowOop* p, oop v) {
   291   OrderAccess::release_store(p, encode_heap_oop(v));
   292 }
   295 // These functions are only used to exchange oop fields in instances,
   296 // not headers.
   297 inline oop oopDesc::atomic_exchange_oop(oop exchange_value, volatile HeapWord *dest) {
   298   if (UseCompressedOops) {
   299     // encode exchange value from oop to T
   300     narrowOop val = encode_heap_oop(exchange_value);
   301     narrowOop old = (narrowOop)Atomic::xchg(val, (narrowOop*)dest);
   302     // decode old from T to oop
   303     return decode_heap_oop(old);
   304   } else {
   305     return (oop)Atomic::xchg_ptr(exchange_value, (oop*)dest);
   306   }
   307 }
   309 // In order to put or get a field out of an instance, must first check
   310 // if the field has been compressed and uncompress it.
   311 inline oop oopDesc::obj_field(int offset) const {
   312   return UseCompressedOops ?
   313     load_decode_heap_oop(obj_field_addr<narrowOop>(offset)) :
   314     load_decode_heap_oop(obj_field_addr<oop>(offset));
   315 }
   316 inline volatile oop oopDesc::obj_field_volatile(int offset) const {
   317   volatile oop value = obj_field(offset);
   318   OrderAccess::acquire();
   319   return value;
   320 }
   321 inline void oopDesc::obj_field_put(int offset, oop value) {
   322   UseCompressedOops ? oop_store(obj_field_addr<narrowOop>(offset), value) :
   323                       oop_store(obj_field_addr<oop>(offset),       value);
   324 }
   326 inline Metadata* oopDesc::metadata_field(int offset) const {
   327   return *metadata_field_addr(offset);
   328 }
   330 inline void oopDesc::metadata_field_put(int offset, Metadata* value) {
   331   *metadata_field_addr(offset) = value;
   332 }
   334 inline void oopDesc::obj_field_put_raw(int offset, oop value) {
   335   UseCompressedOops ?
   336     encode_store_heap_oop(obj_field_addr<narrowOop>(offset), value) :
   337     encode_store_heap_oop(obj_field_addr<oop>(offset),       value);
   338 }
   339 inline void oopDesc::obj_field_put_volatile(int offset, oop value) {
   340   OrderAccess::release();
   341   obj_field_put(offset, value);
   342   OrderAccess::fence();
   343 }
   345 inline jbyte oopDesc::byte_field(int offset) const                  { return (jbyte) *byte_field_addr(offset);    }
   346 inline void oopDesc::byte_field_put(int offset, jbyte contents)     { *byte_field_addr(offset) = (jint) contents; }
   348 inline jboolean oopDesc::bool_field(int offset) const               { return (jboolean) *bool_field_addr(offset); }
   349 inline void oopDesc::bool_field_put(int offset, jboolean contents)  { *bool_field_addr(offset) = (jint) contents; }
   351 inline jchar oopDesc::char_field(int offset) const                  { return (jchar) *char_field_addr(offset);    }
   352 inline void oopDesc::char_field_put(int offset, jchar contents)     { *char_field_addr(offset) = (jint) contents; }
   354 inline jint oopDesc::int_field(int offset) const                    { return *int_field_addr(offset);        }
   355 inline void oopDesc::int_field_put(int offset, jint contents)       { *int_field_addr(offset) = contents;    }
   357 inline jshort oopDesc::short_field(int offset) const                { return (jshort) *short_field_addr(offset);  }
   358 inline void oopDesc::short_field_put(int offset, jshort contents)   { *short_field_addr(offset) = (jint) contents;}
   360 inline jlong oopDesc::long_field(int offset) const                  { return *long_field_addr(offset);       }
   361 inline void oopDesc::long_field_put(int offset, jlong contents)     { *long_field_addr(offset) = contents;   }
   363 inline jfloat oopDesc::float_field(int offset) const                { return *float_field_addr(offset);      }
   364 inline void oopDesc::float_field_put(int offset, jfloat contents)   { *float_field_addr(offset) = contents;  }
   366 inline jdouble oopDesc::double_field(int offset) const              { return *double_field_addr(offset);     }
   367 inline void oopDesc::double_field_put(int offset, jdouble contents) { *double_field_addr(offset) = contents; }
   369 inline address oopDesc::address_field(int offset) const              { return *address_field_addr(offset);     }
   370 inline void oopDesc::address_field_put(int offset, address contents) { *address_field_addr(offset) = contents; }
   372 inline oop oopDesc::obj_field_acquire(int offset) const {
   373   return UseCompressedOops ?
   374              decode_heap_oop((narrowOop)
   375                OrderAccess::load_acquire(obj_field_addr<narrowOop>(offset)))
   376            : decode_heap_oop((oop)
   377                OrderAccess::load_ptr_acquire(obj_field_addr<oop>(offset)));
   378 }
   379 inline void oopDesc::release_obj_field_put(int offset, oop value) {
   380   UseCompressedOops ?
   381     oop_store((volatile narrowOop*)obj_field_addr<narrowOop>(offset), value) :
   382     oop_store((volatile oop*)      obj_field_addr<oop>(offset),       value);
   383 }
   385 inline jbyte oopDesc::byte_field_acquire(int offset) const                  { return OrderAccess::load_acquire(byte_field_addr(offset));     }
   386 inline void oopDesc::release_byte_field_put(int offset, jbyte contents)     { OrderAccess::release_store(byte_field_addr(offset), contents); }
   388 inline jboolean oopDesc::bool_field_acquire(int offset) const               { return OrderAccess::load_acquire(bool_field_addr(offset));     }
   389 inline void oopDesc::release_bool_field_put(int offset, jboolean contents)  { OrderAccess::release_store(bool_field_addr(offset), contents); }
   391 inline jchar oopDesc::char_field_acquire(int offset) const                  { return OrderAccess::load_acquire(char_field_addr(offset));     }
   392 inline void oopDesc::release_char_field_put(int offset, jchar contents)     { OrderAccess::release_store(char_field_addr(offset), contents); }
   394 inline jint oopDesc::int_field_acquire(int offset) const                    { return OrderAccess::load_acquire(int_field_addr(offset));      }
   395 inline void oopDesc::release_int_field_put(int offset, jint contents)       { OrderAccess::release_store(int_field_addr(offset), contents);  }
   397 inline jshort oopDesc::short_field_acquire(int offset) const                { return (jshort)OrderAccess::load_acquire(short_field_addr(offset)); }
   398 inline void oopDesc::release_short_field_put(int offset, jshort contents)   { OrderAccess::release_store(short_field_addr(offset), contents);     }
   400 inline jlong oopDesc::long_field_acquire(int offset) const                  { return OrderAccess::load_acquire(long_field_addr(offset));       }
   401 inline void oopDesc::release_long_field_put(int offset, jlong contents)     { OrderAccess::release_store(long_field_addr(offset), contents);   }
   403 inline jfloat oopDesc::float_field_acquire(int offset) const                { return OrderAccess::load_acquire(float_field_addr(offset));      }
   404 inline void oopDesc::release_float_field_put(int offset, jfloat contents)   { OrderAccess::release_store(float_field_addr(offset), contents);  }
   406 inline jdouble oopDesc::double_field_acquire(int offset) const              { return OrderAccess::load_acquire(double_field_addr(offset));     }
   407 inline void oopDesc::release_double_field_put(int offset, jdouble contents) { OrderAccess::release_store(double_field_addr(offset), contents); }
   409 inline address oopDesc::address_field_acquire(int offset) const             { return (address) OrderAccess::load_ptr_acquire(address_field_addr(offset)); }
   410 inline void oopDesc::release_address_field_put(int offset, address contents) { OrderAccess::release_store_ptr(address_field_addr(offset), contents); }
   412 inline int oopDesc::size_given_klass(Klass* klass)  {
   413   int lh = klass->layout_helper();
   414   int s;
   416   // lh is now a value computed at class initialization that may hint
   417   // at the size.  For instances, this is positive and equal to the
   418   // size.  For arrays, this is negative and provides log2 of the
   419   // array element size.  For other oops, it is zero and thus requires
   420   // a virtual call.
   421   //
   422   // We go to all this trouble because the size computation is at the
   423   // heart of phase 2 of mark-compaction, and called for every object,
   424   // alive or dead.  So the speed here is equal in importance to the
   425   // speed of allocation.
   427   if (lh > Klass::_lh_neutral_value) {
   428     if (!Klass::layout_helper_needs_slow_path(lh)) {
   429       s = lh >> LogHeapWordSize;  // deliver size scaled by wordSize
   430     } else {
   431       s = klass->oop_size(this);
   432     }
   433   } else if (lh <= Klass::_lh_neutral_value) {
   434     // The most common case is instances; fall through if so.
   435     if (lh < Klass::_lh_neutral_value) {
   436       // Second most common case is arrays.  We have to fetch the
   437       // length of the array, shift (multiply) it appropriately,
   438       // up to wordSize, add the header, and align to object size.
   439       size_t size_in_bytes;
   440 #ifdef _M_IA64
   441       // The Windows Itanium Aug 2002 SDK hoists this load above
   442       // the check for s < 0.  An oop at the end of the heap will
   443       // cause an access violation if this load is performed on a non
   444       // array oop.  Making the reference volatile prohibits this.
   445       // (%%% please explain by what magic the length is actually fetched!)
   446       volatile int *array_length;
   447       array_length = (volatile int *)( (intptr_t)this +
   448                           arrayOopDesc::length_offset_in_bytes() );
   449       assert(array_length > 0, "Integer arithmetic problem somewhere");
   450       // Put into size_t to avoid overflow.
   451       size_in_bytes = (size_t) array_length;
   452       size_in_bytes = size_in_bytes << Klass::layout_helper_log2_element_size(lh);
   453 #else
   454       size_t array_length = (size_t) ((arrayOop)this)->length();
   455       size_in_bytes = array_length << Klass::layout_helper_log2_element_size(lh);
   456 #endif
   457       size_in_bytes += Klass::layout_helper_header_size(lh);
   459       // This code could be simplified, but by keeping array_header_in_bytes
   460       // in units of bytes and doing it this way we can round up just once,
   461       // skipping the intermediate round to HeapWordSize.  Cast the result
   462       // of round_to to size_t to guarantee unsigned division == right shift.
   463       s = (int)((size_t)round_to(size_in_bytes, MinObjAlignmentInBytes) /
   464         HeapWordSize);
   466       // UseParNewGC, UseParallelGC and UseG1GC can change the length field
   467       // of an "old copy" of an object array in the young gen so it indicates
   468       // the grey portion of an already copied array. This will cause the first
   469       // disjunct below to fail if the two comparands are computed across such
   470       // a concurrent change.
   471       // UseParNewGC also runs with promotion labs (which look like int
   472       // filler arrays) which are subject to changing their declared size
   473       // when finally retiring a PLAB; this also can cause the first disjunct
   474       // to fail for another worker thread that is concurrently walking the block
   475       // offset table. Both these invariant failures are benign for their
   476       // current uses; we relax the assertion checking to cover these two cases below:
   477       //     is_objArray() && is_forwarded()   // covers first scenario above
   478       //  || is_typeArray()                    // covers second scenario above
   479       // If and when UseParallelGC uses the same obj array oop stealing/chunking
   480       // technique, we will need to suitably modify the assertion.
   481       assert((s == klass->oop_size(this)) ||
   482              (Universe::heap()->is_gc_active() &&
   483               ((is_typeArray() && UseParNewGC) ||
   484                (is_objArray()  && is_forwarded() && (UseParNewGC || UseParallelGC || UseG1GC)))),
   485              "wrong array object size");
   486     } else {
   487       // Must be zero, so bite the bullet and take the virtual call.
   488       s = klass->oop_size(this);
   489     }
   490   }
   492   assert(s % MinObjAlignment == 0, "alignment check");
   493   assert(s > 0, "Bad size calculated");
   494   return s;
   495 }
   498 inline int oopDesc::size()  {
   499   return size_given_klass(klass());
   500 }
   502 inline void update_barrier_set(void* p, oop v, bool release = false) {
   503   assert(oopDesc::bs() != NULL, "Uninitialized bs in oop!");
   504   oopDesc::bs()->write_ref_field(p, v, release);
   505 }
   507 template <class T> inline void update_barrier_set_pre(T* p, oop v) {
   508   oopDesc::bs()->write_ref_field_pre(p, v);
   509 }
   511 template <class T> inline void oop_store(T* p, oop v) {
   512   if (always_do_update_barrier) {
   513     oop_store((volatile T*)p, v);
   514   } else {
   515     update_barrier_set_pre(p, v);
   516     oopDesc::encode_store_heap_oop(p, v);
   517     // always_do_update_barrier == false =>
   518     // Either we are at a safepoint (in GC) or CMS is not used. In both
   519     // cases it's unnecessary to mark the card as dirty with release sematics.
   520     update_barrier_set((void*)p, v, false /* release */);  // cast away type
   521   }
   522 }
   524 template <class T> inline void oop_store(volatile T* p, oop v) {
   525   update_barrier_set_pre((T*)p, v);   // cast away volatile
   526   // Used by release_obj_field_put, so use release_store_ptr.
   527   oopDesc::release_encode_store_heap_oop(p, v);
   528   // When using CMS we must mark the card corresponding to p as dirty
   529   // with release sematics to prevent that CMS sees the dirty card but
   530   // not the new value v at p due to reordering of the two
   531   // stores. Note that CMS has a concurrent precleaning phase, where
   532   // it reads the card table while the Java threads are running.
   533   update_barrier_set((void*)p, v, true /* release */);    // cast away type
   534 }
   536 // Should replace *addr = oop assignments where addr type depends on UseCompressedOops
   537 // (without having to remember the function name this calls).
   538 inline void oop_store_raw(HeapWord* addr, oop value) {
   539   if (UseCompressedOops) {
   540     oopDesc::encode_store_heap_oop((narrowOop*)addr, value);
   541   } else {
   542     oopDesc::encode_store_heap_oop((oop*)addr, value);
   543   }
   544 }
   546 inline oop oopDesc::atomic_compare_exchange_oop(oop exchange_value,
   547                                                 volatile HeapWord *dest,
   548                                                 oop compare_value,
   549                                                 bool prebarrier) {
   550   if (UseCompressedOops) {
   551     if (prebarrier) {
   552       update_barrier_set_pre((narrowOop*)dest, exchange_value);
   553     }
   554     // encode exchange and compare value from oop to T
   555     narrowOop val = encode_heap_oop(exchange_value);
   556     narrowOop cmp = encode_heap_oop(compare_value);
   558     narrowOop old = (narrowOop) Atomic::cmpxchg(val, (narrowOop*)dest, cmp);
   559     // decode old from T to oop
   560     return decode_heap_oop(old);
   561   } else {
   562     if (prebarrier) {
   563       update_barrier_set_pre((oop*)dest, exchange_value);
   564     }
   565     return (oop)Atomic::cmpxchg_ptr(exchange_value, (oop*)dest, compare_value);
   566   }
   567 }
   569 // Used only for markSweep, scavenging
   570 inline bool oopDesc::is_gc_marked() const {
   571   return mark()->is_marked();
   572 }
   574 inline bool oopDesc::is_locked() const {
   575   return mark()->is_locked();
   576 }
   578 inline bool oopDesc::is_unlocked() const {
   579   return mark()->is_unlocked();
   580 }
   582 inline bool oopDesc::has_bias_pattern() const {
   583   return mark()->has_bias_pattern();
   584 }
   587 // used only for asserts
   588 inline bool oopDesc::is_oop(bool ignore_mark_word) const {
   589   oop obj = (oop) this;
   590   if (!check_obj_alignment(obj)) return false;
   591   if (!Universe::heap()->is_in_reserved(obj)) return false;
   592   // obj is aligned and accessible in heap
   593   if (Universe::heap()->is_in_reserved(obj->klass_or_null())) return false;
   595   // Header verification: the mark is typically non-NULL. If we're
   596   // at a safepoint, it must not be null.
   597   // Outside of a safepoint, the header could be changing (for example,
   598   // another thread could be inflating a lock on this object).
   599   if (ignore_mark_word) {
   600     return true;
   601   }
   602   if (mark() != NULL) {
   603     return true;
   604   }
   605   return !SafepointSynchronize::is_at_safepoint();
   606 }
   609 // used only for asserts
   610 inline bool oopDesc::is_oop_or_null(bool ignore_mark_word) const {
   611   return this == NULL ? true : is_oop(ignore_mark_word);
   612 }
   614 #ifndef PRODUCT
   615 // used only for asserts
   616 inline bool oopDesc::is_unlocked_oop() const {
   617   if (!Universe::heap()->is_in_reserved(this)) return false;
   618   return mark()->is_unlocked();
   619 }
   620 #endif // PRODUCT
   622 inline void oopDesc::follow_contents(void) {
   623   assert (is_gc_marked(), "should be marked");
   624   klass()->oop_follow_contents(this);
   625 }
   627 // Used by scavengers
   629 inline bool oopDesc::is_forwarded() const {
   630   // The extra heap check is needed since the obj might be locked, in which case the
   631   // mark would point to a stack location and have the sentinel bit cleared
   632   return mark()->is_marked();
   633 }
   635 // Used by scavengers
   636 inline void oopDesc::forward_to(oop p) {
   637   assert(check_obj_alignment(p),
   638          "forwarding to something not aligned");
   639   assert(Universe::heap()->is_in_reserved(p),
   640          "forwarding to something not in heap");
   641   markOop m = markOopDesc::encode_pointer_as_mark(p);
   642   assert(m->decode_pointer() == p, "encoding must be reversable");
   643   set_mark(m);
   644 }
   646 // Used by parallel scavengers
   647 inline bool oopDesc::cas_forward_to(oop p, markOop compare) {
   648   assert(check_obj_alignment(p),
   649          "forwarding to something not aligned");
   650   assert(Universe::heap()->is_in_reserved(p),
   651          "forwarding to something not in heap");
   652   markOop m = markOopDesc::encode_pointer_as_mark(p);
   653   assert(m->decode_pointer() == p, "encoding must be reversable");
   654   return cas_set_mark(m, compare) == compare;
   655 }
   657 // Note that the forwardee is not the same thing as the displaced_mark.
   658 // The forwardee is used when copying during scavenge and mark-sweep.
   659 // It does need to clear the low two locking- and GC-related bits.
   660 inline oop oopDesc::forwardee() const {
   661   return (oop) mark()->decode_pointer();
   662 }
   664 inline bool oopDesc::has_displaced_mark() const {
   665   return mark()->has_displaced_mark_helper();
   666 }
   668 inline markOop oopDesc::displaced_mark() const {
   669   return mark()->displaced_mark_helper();
   670 }
   672 inline void oopDesc::set_displaced_mark(markOop m) {
   673   mark()->set_displaced_mark_helper(m);
   674 }
   676 // The following method needs to be MT safe.
   677 inline uint oopDesc::age() const {
   678   assert(!is_forwarded(), "Attempt to read age from forwarded mark");
   679   if (has_displaced_mark()) {
   680     return displaced_mark()->age();
   681   } else {
   682     return mark()->age();
   683   }
   684 }
   686 inline void oopDesc::incr_age() {
   687   assert(!is_forwarded(), "Attempt to increment age of forwarded mark");
   688   if (has_displaced_mark()) {
   689     set_displaced_mark(displaced_mark()->incr_age());
   690   } else {
   691     set_mark(mark()->incr_age());
   692   }
   693 }
   696 inline intptr_t oopDesc::identity_hash() {
   697   // Fast case; if the object is unlocked and the hash value is set, no locking is needed
   698   // Note: The mark must be read into local variable to avoid concurrent updates.
   699   markOop mrk = mark();
   700   if (mrk->is_unlocked() && !mrk->has_no_hash()) {
   701     return mrk->hash();
   702   } else if (mrk->is_marked()) {
   703     return mrk->hash();
   704   } else {
   705     return slow_identity_hash();
   706   }
   707 }
   709 inline int oopDesc::adjust_pointers() {
   710   debug_only(int check_size = size());
   711   int s = klass()->oop_adjust_pointers(this);
   712   assert(s == check_size, "should be the same");
   713   return s;
   714 }
   716 #define OOP_ITERATE_DEFN(OopClosureType, nv_suffix)                        \
   717                                                                            \
   718 inline int oopDesc::oop_iterate(OopClosureType* blk) {                     \
   719   SpecializationStats::record_call();                                      \
   720   return klass()->oop_oop_iterate##nv_suffix(this, blk);               \
   721 }                                                                          \
   722                                                                            \
   723 inline int oopDesc::oop_iterate(OopClosureType* blk, MemRegion mr) {       \
   724   SpecializationStats::record_call();                                      \
   725   return klass()->oop_oop_iterate##nv_suffix##_m(this, blk, mr);       \
   726 }
   729 inline int oopDesc::oop_iterate_no_header(OopClosure* blk) {
   730   // The NoHeaderExtendedOopClosure wraps the OopClosure and proxies all
   731   // the do_oop calls, but turns off all other features in ExtendedOopClosure.
   732   NoHeaderExtendedOopClosure cl(blk);
   733   return oop_iterate(&cl);
   734 }
   736 inline int oopDesc::oop_iterate_no_header(OopClosure* blk, MemRegion mr) {
   737   NoHeaderExtendedOopClosure cl(blk);
   738   return oop_iterate(&cl, mr);
   739 }
   741 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_DEFN)
   742 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_DEFN)
   744 #if INCLUDE_ALL_GCS
   745 #define OOP_ITERATE_BACKWARDS_DEFN(OopClosureType, nv_suffix)              \
   746                                                                            \
   747 inline int oopDesc::oop_iterate_backwards(OopClosureType* blk) {           \
   748   SpecializationStats::record_call();                                      \
   749   return klass()->oop_oop_iterate_backwards##nv_suffix(this, blk);     \
   750 }
   752 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_BACKWARDS_DEFN)
   753 ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_BACKWARDS_DEFN)
   754 #endif // INCLUDE_ALL_GCS
   756 #endif // SHARE_VM_OOPS_OOP_INLINE_HPP

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