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

Sun, 13 Apr 2008 17:43:42 -0400

author
coleenp
date
Sun, 13 Apr 2008 17:43:42 -0400
changeset 548
ba764ed4b6f2
parent 435
a61af66fc99e
child 568
435e64505015
permissions
-rw-r--r--

6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
Summary: Compressed oops in instances, arrays, and headers. Code contributors are coleenp, phh, never, swamyv
Reviewed-by: jmasa, kamg, acorn, tbell, kvn, rasbold

     1 /*
     2  * Copyright 1997-2007 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
    20  * CA 95054 USA or visit www.sun.com if you need additional information or
    21  * have any questions.
    22  *
    23  */
    25 // Implementation of all inlined member functions defined in oop.hpp
    26 // We need a separate file to avoid circular references
    28 inline void oopDesc::release_set_mark(markOop m) {
    29   OrderAccess::release_store_ptr(&_mark, m);
    30 }
    32 inline markOop oopDesc::cas_set_mark(markOop new_mark, markOop old_mark) {
    33   return (markOop) Atomic::cmpxchg_ptr(new_mark, &_mark, old_mark);
    34 }
    36 inline klassOop oopDesc::klass() const {
    37   if (UseCompressedOops) {
    38     return (klassOop)decode_heap_oop_not_null(_metadata._compressed_klass);
    39       // can be NULL in CMS, but isn't supported on CMS yet.
    40   } else {
    41     return _metadata._klass;
    42   }
    43 }
    45 inline int oopDesc::klass_gap_offset_in_bytes() {
    46   assert(UseCompressedOops, "only applicable to compressed headers");
    47   return oopDesc::klass_offset_in_bytes() + sizeof(narrowOop);
    48 }
    50 inline oop* oopDesc::klass_addr() {
    51   // Only used internally and with CMS and will not work with
    52   // UseCompressedOops
    53   assert(!UseCompressedOops, "only supported with uncompressed oops");
    54   return (oop*) &_metadata._klass;
    55 }
    57 inline narrowOop* oopDesc::compressed_klass_addr() {
    58   assert(UseCompressedOops, "only called by compressed oops");
    59   return (narrowOop*) &_metadata._compressed_klass;
    60 }
    62 inline void oopDesc::set_klass(klassOop k) {
    63   // since klasses are promoted no store check is needed
    64   assert(Universe::is_bootstrapping() || k != NULL, "must be a real klassOop");
    65   assert(Universe::is_bootstrapping() || k->is_klass(), "not a klassOop");
    66   if (UseCompressedOops) {
    67     // zero the gap when the klass is set, by zeroing the pointer sized
    68     // part of the union.
    69     _metadata._klass = NULL;
    70     oop_store_without_check(compressed_klass_addr(), (oop)k);
    71   } else {
    72     oop_store_without_check(klass_addr(), (oop) k);
    73   }
    74 }
    76 inline void oopDesc::set_klass_to_list_ptr(oop k) {
    77   // This is only to be used during GC, for from-space objects, so no
    78   // barrier is needed.
    79   if (UseCompressedOops) {
    80     _metadata._compressed_klass = encode_heap_oop_not_null(k);
    81   } else {
    82     _metadata._klass = (klassOop)k;
    83   }
    84 }
    86 inline void   oopDesc::init_mark()                 { set_mark(markOopDesc::prototype_for_object(this)); }
    87 inline Klass* oopDesc::blueprint()           const { return klass()->klass_part(); }
    89 inline bool oopDesc::is_a(klassOop k)        const { return blueprint()->is_subtype_of(k); }
    91 inline bool oopDesc::is_instance()           const { return blueprint()->oop_is_instance(); }
    92 inline bool oopDesc::is_instanceRef()        const { return blueprint()->oop_is_instanceRef(); }
    93 inline bool oopDesc::is_array()              const { return blueprint()->oop_is_array(); }
    94 inline bool oopDesc::is_objArray()           const { return blueprint()->oop_is_objArray(); }
    95 inline bool oopDesc::is_typeArray()          const { return blueprint()->oop_is_typeArray(); }
    96 inline bool oopDesc::is_javaArray()          const { return blueprint()->oop_is_javaArray(); }
    97 inline bool oopDesc::is_symbol()             const { return blueprint()->oop_is_symbol(); }
    98 inline bool oopDesc::is_klass()              const { return blueprint()->oop_is_klass(); }
    99 inline bool oopDesc::is_thread()             const { return blueprint()->oop_is_thread(); }
   100 inline bool oopDesc::is_method()             const { return blueprint()->oop_is_method(); }
   101 inline bool oopDesc::is_constMethod()        const { return blueprint()->oop_is_constMethod(); }
   102 inline bool oopDesc::is_methodData()         const { return blueprint()->oop_is_methodData(); }
   103 inline bool oopDesc::is_constantPool()       const { return blueprint()->oop_is_constantPool(); }
   104 inline bool oopDesc::is_constantPoolCache()  const { return blueprint()->oop_is_constantPoolCache(); }
   105 inline bool oopDesc::is_compiledICHolder()   const { return blueprint()->oop_is_compiledICHolder(); }
   107 inline void*     oopDesc::field_base(int offset)        const { return (void*)&((char*)this)[offset]; }
   109 template <class T> inline T* oopDesc::obj_field_addr(int offset) const { return (T*)field_base(offset); }
   110 inline jbyte*    oopDesc::byte_field_addr(int offset)   const { return (jbyte*)   field_base(offset); }
   111 inline jchar*    oopDesc::char_field_addr(int offset)   const { return (jchar*)   field_base(offset); }
   112 inline jboolean* oopDesc::bool_field_addr(int offset)   const { return (jboolean*)field_base(offset); }
   113 inline jint*     oopDesc::int_field_addr(int offset)    const { return (jint*)    field_base(offset); }
   114 inline jshort*   oopDesc::short_field_addr(int offset)  const { return (jshort*)  field_base(offset); }
   115 inline jlong*    oopDesc::long_field_addr(int offset)   const { return (jlong*)   field_base(offset); }
   116 inline jfloat*   oopDesc::float_field_addr(int offset)  const { return (jfloat*)  field_base(offset); }
   117 inline jdouble*  oopDesc::double_field_addr(int offset) const { return (jdouble*) field_base(offset); }
   118 inline address*  oopDesc::address_field_addr(int offset) const { return (address*) field_base(offset); }
   121 // Functions for getting and setting oops within instance objects.
   122 // If the oops are compressed, the type passed to these overloaded functions
   123 // is narrowOop.  All functions are overloaded so they can be called by
   124 // template functions without conditionals (the compiler instantiates via
   125 // the right type and inlines the appopriate code).
   127 inline bool oopDesc::is_null(oop obj)       { return obj == NULL; }
   128 inline bool oopDesc::is_null(narrowOop obj) { return obj == 0; }
   130 // Algorithm for encoding and decoding oops from 64 bit pointers to 32 bit
   131 // offset from the heap base.  Saving the check for null can save instructions
   132 // in inner GC loops so these are separated.
   134 inline narrowOop oopDesc::encode_heap_oop_not_null(oop v) {
   135   assert(!is_null(v), "oop value can never be zero");
   136   address heap_base = Universe::heap_base();
   137   uint64_t result = (uint64_t)(pointer_delta((void*)v, (void*)heap_base, 1) >> LogMinObjAlignmentInBytes);
   138   assert((result & 0xffffffff00000000L) == 0, "narrow oop overflow");
   139   return (narrowOop)result;
   140 }
   142 inline narrowOop oopDesc::encode_heap_oop(oop v) {
   143   return (is_null(v)) ? (narrowOop)0 : encode_heap_oop_not_null(v);
   144 }
   146 inline oop oopDesc::decode_heap_oop_not_null(narrowOop v) {
   147   assert(!is_null(v), "narrow oop value can never be zero");
   148   address heap_base = Universe::heap_base();
   149   return (oop)(void*)((uintptr_t)heap_base + ((uintptr_t)v << LogMinObjAlignmentInBytes));
   150 }
   152 inline oop oopDesc::decode_heap_oop(narrowOop v) {
   153   return is_null(v) ? (oop)NULL : decode_heap_oop_not_null(v);
   154 }
   156 inline oop oopDesc::decode_heap_oop_not_null(oop v) { return v; }
   157 inline oop oopDesc::decode_heap_oop(oop v)  { return v; }
   159 // Load an oop out of the Java heap as is without decoding.
   160 // Called by GC to check for null before decoding.
   161 inline oop       oopDesc::load_heap_oop(oop* p)          { return *p; }
   162 inline narrowOop oopDesc::load_heap_oop(narrowOop* p)    { return *p; }
   164 // Load and decode an oop out of the Java heap into a wide oop.
   165 inline oop oopDesc::load_decode_heap_oop_not_null(oop* p)       { return *p; }
   166 inline oop oopDesc::load_decode_heap_oop_not_null(narrowOop* p) {
   167   return decode_heap_oop_not_null(*p);
   168 }
   170 // Load and decode an oop out of the heap accepting null
   171 inline oop oopDesc::load_decode_heap_oop(oop* p) { return *p; }
   172 inline oop oopDesc::load_decode_heap_oop(narrowOop* p) {
   173   return decode_heap_oop(*p);
   174 }
   176 // Store already encoded heap oop into the heap.
   177 inline void oopDesc::store_heap_oop(oop* p, oop v)                 { *p = v; }
   178 inline void oopDesc::store_heap_oop(narrowOop* p, narrowOop v)     { *p = v; }
   180 // Encode and store a heap oop.
   181 inline void oopDesc::encode_store_heap_oop_not_null(narrowOop* p, oop v) {
   182   *p = encode_heap_oop_not_null(v);
   183 }
   184 inline void oopDesc::encode_store_heap_oop_not_null(oop* p, oop v) { *p = v; }
   186 // Encode and store a heap oop allowing for null.
   187 inline void oopDesc::encode_store_heap_oop(narrowOop* p, oop v) {
   188   *p = encode_heap_oop(v);
   189 }
   190 inline void oopDesc::encode_store_heap_oop(oop* p, oop v) { *p = v; }
   192 // Store heap oop as is for volatile fields.
   193 inline void oopDesc::release_store_heap_oop(volatile oop* p, oop v) {
   194   OrderAccess::release_store_ptr(p, v);
   195 }
   196 inline void oopDesc::release_store_heap_oop(volatile narrowOop* p,
   197                                             narrowOop v) {
   198   OrderAccess::release_store(p, v);
   199 }
   201 inline void oopDesc::release_encode_store_heap_oop_not_null(
   202                                                 volatile narrowOop* p, oop v) {
   203   // heap oop is not pointer sized.
   204   OrderAccess::release_store(p, encode_heap_oop_not_null(v));
   205 }
   207 inline void oopDesc::release_encode_store_heap_oop_not_null(
   208                                                       volatile oop* p, oop v) {
   209   OrderAccess::release_store_ptr(p, v);
   210 }
   212 inline void oopDesc::release_encode_store_heap_oop(volatile oop* p,
   213                                                            oop v) {
   214   OrderAccess::release_store_ptr(p, v);
   215 }
   216 inline void oopDesc::release_encode_store_heap_oop(
   217                                                 volatile narrowOop* p, oop v) {
   218   OrderAccess::release_store(p, encode_heap_oop(v));
   219 }
   222 // These functions are only used to exchange oop fields in instances,
   223 // not headers.
   224 inline oop oopDesc::atomic_exchange_oop(oop exchange_value, volatile HeapWord *dest) {
   225   if (UseCompressedOops) {
   226     // encode exchange value from oop to T
   227     narrowOop val = encode_heap_oop(exchange_value);
   228     narrowOop old = (narrowOop)Atomic::xchg(val, (narrowOop*)dest);
   229     // decode old from T to oop
   230     return decode_heap_oop(old);
   231   } else {
   232     return (oop)Atomic::xchg_ptr(exchange_value, (oop*)dest);
   233   }
   234 }
   236 inline oop oopDesc::atomic_compare_exchange_oop(oop exchange_value,
   237                                                 volatile HeapWord *dest,
   238                                                 oop compare_value) {
   239   if (UseCompressedOops) {
   240     // encode exchange and compare value from oop to T
   241     narrowOop val = encode_heap_oop(exchange_value);
   242     narrowOop cmp = encode_heap_oop(compare_value);
   244     narrowOop old = (narrowOop) Atomic::cmpxchg(val, (narrowOop*)dest, cmp);
   245     // decode old from T to oop
   246     return decode_heap_oop(old);
   247   } else {
   248     return (oop)Atomic::cmpxchg_ptr(exchange_value, (oop*)dest, compare_value);
   249   }
   250 }
   252 // In order to put or get a field out of an instance, must first check
   253 // if the field has been compressed and uncompress it.
   254 inline oop oopDesc::obj_field(int offset) const {
   255   return UseCompressedOops ?
   256     load_decode_heap_oop(obj_field_addr<narrowOop>(offset)) :
   257     load_decode_heap_oop(obj_field_addr<oop>(offset));
   258 }
   259 inline void oopDesc::obj_field_put(int offset, oop value) {
   260   UseCompressedOops ? oop_store(obj_field_addr<narrowOop>(offset), value) :
   261                       oop_store(obj_field_addr<oop>(offset),       value);
   262 }
   263 inline void oopDesc::obj_field_raw_put(int offset, oop value) {
   264   UseCompressedOops ?
   265     encode_store_heap_oop(obj_field_addr<narrowOop>(offset), value) :
   266     encode_store_heap_oop(obj_field_addr<oop>(offset),       value);
   267 }
   269 inline jbyte oopDesc::byte_field(int offset) const                  { return (jbyte) *byte_field_addr(offset);    }
   270 inline void oopDesc::byte_field_put(int offset, jbyte contents)     { *byte_field_addr(offset) = (jint) contents; }
   272 inline jboolean oopDesc::bool_field(int offset) const               { return (jboolean) *bool_field_addr(offset); }
   273 inline void oopDesc::bool_field_put(int offset, jboolean contents)  { *bool_field_addr(offset) = (jint) contents; }
   275 inline jchar oopDesc::char_field(int offset) const                  { return (jchar) *char_field_addr(offset);    }
   276 inline void oopDesc::char_field_put(int offset, jchar contents)     { *char_field_addr(offset) = (jint) contents; }
   278 inline jint oopDesc::int_field(int offset) const                    { return *int_field_addr(offset);        }
   279 inline void oopDesc::int_field_put(int offset, jint contents)       { *int_field_addr(offset) = contents;    }
   281 inline jshort oopDesc::short_field(int offset) const                { return (jshort) *short_field_addr(offset);  }
   282 inline void oopDesc::short_field_put(int offset, jshort contents)   { *short_field_addr(offset) = (jint) contents;}
   284 inline jlong oopDesc::long_field(int offset) const                  { return *long_field_addr(offset);       }
   285 inline void oopDesc::long_field_put(int offset, jlong contents)     { *long_field_addr(offset) = contents;   }
   287 inline jfloat oopDesc::float_field(int offset) const                { return *float_field_addr(offset);      }
   288 inline void oopDesc::float_field_put(int offset, jfloat contents)   { *float_field_addr(offset) = contents;  }
   290 inline jdouble oopDesc::double_field(int offset) const              { return *double_field_addr(offset);     }
   291 inline void oopDesc::double_field_put(int offset, jdouble contents) { *double_field_addr(offset) = contents; }
   293 inline address oopDesc::address_field(int offset) const              { return *address_field_addr(offset);     }
   294 inline void oopDesc::address_field_put(int offset, address contents) { *address_field_addr(offset) = contents; }
   296 inline oop oopDesc::obj_field_acquire(int offset) const {
   297   return UseCompressedOops ?
   298              decode_heap_oop((narrowOop)
   299                OrderAccess::load_acquire(obj_field_addr<narrowOop>(offset)))
   300            : decode_heap_oop((oop)
   301                OrderAccess::load_ptr_acquire(obj_field_addr<oop>(offset)));
   302 }
   303 inline void oopDesc::release_obj_field_put(int offset, oop value) {
   304   UseCompressedOops ?
   305     oop_store((volatile narrowOop*)obj_field_addr<narrowOop>(offset), value) :
   306     oop_store((volatile oop*)      obj_field_addr<oop>(offset),       value);
   307 }
   309 inline jbyte oopDesc::byte_field_acquire(int offset) const                  { return OrderAccess::load_acquire(byte_field_addr(offset));     }
   310 inline void oopDesc::release_byte_field_put(int offset, jbyte contents)     { OrderAccess::release_store(byte_field_addr(offset), contents); }
   312 inline jboolean oopDesc::bool_field_acquire(int offset) const               { return OrderAccess::load_acquire(bool_field_addr(offset));     }
   313 inline void oopDesc::release_bool_field_put(int offset, jboolean contents)  { OrderAccess::release_store(bool_field_addr(offset), contents); }
   315 inline jchar oopDesc::char_field_acquire(int offset) const                  { return OrderAccess::load_acquire(char_field_addr(offset));     }
   316 inline void oopDesc::release_char_field_put(int offset, jchar contents)     { OrderAccess::release_store(char_field_addr(offset), contents); }
   318 inline jint oopDesc::int_field_acquire(int offset) const                    { return OrderAccess::load_acquire(int_field_addr(offset));      }
   319 inline void oopDesc::release_int_field_put(int offset, jint contents)       { OrderAccess::release_store(int_field_addr(offset), contents);  }
   321 inline jshort oopDesc::short_field_acquire(int offset) const                { return (jshort)OrderAccess::load_acquire(short_field_addr(offset)); }
   322 inline void oopDesc::release_short_field_put(int offset, jshort contents)   { OrderAccess::release_store(short_field_addr(offset), contents);     }
   324 inline jlong oopDesc::long_field_acquire(int offset) const                  { return OrderAccess::load_acquire(long_field_addr(offset));       }
   325 inline void oopDesc::release_long_field_put(int offset, jlong contents)     { OrderAccess::release_store(long_field_addr(offset), contents);   }
   327 inline jfloat oopDesc::float_field_acquire(int offset) const                { return OrderAccess::load_acquire(float_field_addr(offset));      }
   328 inline void oopDesc::release_float_field_put(int offset, jfloat contents)   { OrderAccess::release_store(float_field_addr(offset), contents);  }
   330 inline jdouble oopDesc::double_field_acquire(int offset) const              { return OrderAccess::load_acquire(double_field_addr(offset));     }
   331 inline void oopDesc::release_double_field_put(int offset, jdouble contents) { OrderAccess::release_store(double_field_addr(offset), contents); }
   333 inline int oopDesc::size_given_klass(Klass* klass)  {
   334   int lh = klass->layout_helper();
   335   int s  = lh >> LogHeapWordSize;  // deliver size scaled by wordSize
   337   // lh is now a value computed at class initialization that may hint
   338   // at the size.  For instances, this is positive and equal to the
   339   // size.  For arrays, this is negative and provides log2 of the
   340   // array element size.  For other oops, it is zero and thus requires
   341   // a virtual call.
   342   //
   343   // We go to all this trouble because the size computation is at the
   344   // heart of phase 2 of mark-compaction, and called for every object,
   345   // alive or dead.  So the speed here is equal in importance to the
   346   // speed of allocation.
   348   if (lh <= Klass::_lh_neutral_value) {
   349     // The most common case is instances; fall through if so.
   350     if (lh < Klass::_lh_neutral_value) {
   351       // Second most common case is arrays.  We have to fetch the
   352       // length of the array, shift (multiply) it appropriately,
   353       // up to wordSize, add the header, and align to object size.
   354       size_t size_in_bytes;
   355 #ifdef _M_IA64
   356       // The Windows Itanium Aug 2002 SDK hoists this load above
   357       // the check for s < 0.  An oop at the end of the heap will
   358       // cause an access violation if this load is performed on a non
   359       // array oop.  Making the reference volatile prohibits this.
   360       // (%%% please explain by what magic the length is actually fetched!)
   361       volatile int *array_length;
   362       array_length = (volatile int *)( (intptr_t)this +
   363                           arrayOopDesc::length_offset_in_bytes() );
   364       assert(array_length > 0, "Integer arithmetic problem somewhere");
   365       // Put into size_t to avoid overflow.
   366       size_in_bytes = (size_t) array_length;
   367       size_in_bytes = size_in_bytes << Klass::layout_helper_log2_element_size(lh);
   368 #else
   369       size_t array_length = (size_t) ((arrayOop)this)->length();
   370       size_in_bytes = array_length << Klass::layout_helper_log2_element_size(lh);
   371 #endif
   372       size_in_bytes += Klass::layout_helper_header_size(lh);
   374       // This code could be simplified, but by keeping array_header_in_bytes
   375       // in units of bytes and doing it this way we can round up just once,
   376       // skipping the intermediate round to HeapWordSize.  Cast the result
   377       // of round_to to size_t to guarantee unsigned division == right shift.
   378       s = (int)((size_t)round_to(size_in_bytes, MinObjAlignmentInBytes) /
   379         HeapWordSize);
   381       // UseParNewGC can change the length field of an "old copy" of an object
   382       // array in the young gen so it indicates the stealable portion of
   383       // an already copied array. This will cause the first disjunct below
   384       // to fail if the sizes are computed across such a concurrent change.
   385       // UseParNewGC also runs with promotion labs (which look like int
   386       // filler arrays) which are subject to changing their declared size
   387       // when finally retiring a PLAB; this also can cause the first disjunct
   388       // to fail for another worker thread that is concurrently walking the block
   389       // offset table. Both these invariant failures are benign for their
   390       // current uses; we relax the assertion checking to cover these two cases below:
   391       //     is_objArray() && is_forwarded()   // covers first scenario above
   392       //  || is_typeArray()                    // covers second scenario above
   393       // If and when UseParallelGC uses the same obj array oop stealing/chunking
   394       // technique, or when G1 is integrated (and currently uses this array chunking
   395       // technique) we will need to suitably modify the assertion.
   396       assert((s == klass->oop_size(this)) ||
   397              (((UseParNewGC || UseParallelGC) &&
   398               Universe::heap()->is_gc_active()) &&
   399               (is_typeArray() ||
   400                (is_objArray() && is_forwarded()))),
   401              "wrong array object size");
   402     } else {
   403       // Must be zero, so bite the bullet and take the virtual call.
   404       s = klass->oop_size(this);
   405     }
   406   }
   408   assert(s % MinObjAlignment == 0, "alignment check");
   409   assert(s > 0, "Bad size calculated");
   410   return s;
   411 }
   414 inline int oopDesc::size()  {
   415   return size_given_klass(blueprint());
   416 }
   418 inline bool oopDesc::is_parsable() {
   419   return blueprint()->oop_is_parsable(this);
   420 }
   422 inline void update_barrier_set(void* p, oop v) {
   423   assert(oopDesc::bs() != NULL, "Uninitialized bs in oop!");
   424   oopDesc::bs()->write_ref_field(p, v);
   425 }
   427 template <class T> inline void oop_store(T* p, oop v) {
   428   if (always_do_update_barrier) {
   429     oop_store((volatile T*)p, v);
   430   } else {
   431     oopDesc::encode_store_heap_oop(p, v);
   432     update_barrier_set(p, v);
   433   }
   434 }
   436 template <class T> inline void oop_store(volatile T* p, oop v) {
   437   // Used by release_obj_field_put, so use release_store_ptr.
   438   oopDesc::release_encode_store_heap_oop(p, v);
   439   update_barrier_set((void*)p, v);
   440 }
   442 template <class T> inline void oop_store_without_check(T* p, oop v) {
   443   // XXX YSR FIX ME!!!
   444   if (always_do_update_barrier) {
   445     oop_store(p, v);
   446   } else {
   447     assert(!Universe::heap()->barrier_set()->write_ref_needs_barrier(p, v),
   448            "oop store without store check failed");
   449     oopDesc::encode_store_heap_oop(p, v);
   450   }
   451 }
   453 // When it absolutely has to get there.
   454 template <class T> inline void oop_store_without_check(volatile T* p, oop v) {
   455   // XXX YSR FIX ME!!!
   456   if (always_do_update_barrier) {
   457     oop_store(p, v);
   458   } else {
   459     assert(!Universe::heap()->barrier_set()->write_ref_needs_barrier((T*)p, v),
   460            "oop store without store check failed");
   461     oopDesc::release_encode_store_heap_oop(p, v);
   462   }
   463 }
   465 // Should replace *addr = oop assignments where addr type depends on UseCompressedOops
   466 // (without having to remember the function name this calls).
   467 inline void oop_store_raw(HeapWord* addr, oop value) {
   468   if (UseCompressedOops) {
   469     oopDesc::encode_store_heap_oop((narrowOop*)addr, value);
   470   } else {
   471     oopDesc::encode_store_heap_oop((oop*)addr, value);
   472   }
   473 }
   475 // Used only for markSweep, scavenging
   476 inline bool oopDesc::is_gc_marked() const {
   477   return mark()->is_marked();
   478 }
   480 inline bool oopDesc::is_locked() const {
   481   return mark()->is_locked();
   482 }
   484 inline bool oopDesc::is_unlocked() const {
   485   return mark()->is_unlocked();
   486 }
   488 inline bool oopDesc::has_bias_pattern() const {
   489   return mark()->has_bias_pattern();
   490 }
   492 inline bool check_obj_alignment(oop obj) {
   493   return (intptr_t)obj % MinObjAlignmentInBytes == 0;
   494 }
   497 // used only for asserts
   498 inline bool oopDesc::is_oop(bool ignore_mark_word) const {
   499   oop obj = (oop) this;
   500   if (!check_obj_alignment(obj)) return false;
   501   if (!Universe::heap()->is_in_reserved(obj)) return false;
   502   // obj is aligned and accessible in heap
   503   // try to find metaclass cycle safely without seg faulting on bad input
   504   // we should reach klassKlassObj by following klass link at most 3 times
   505   for (int i = 0; i < 3; i++) {
   506     obj = obj->klass();
   507     // klass should be aligned and in permspace
   508     if (!check_obj_alignment(obj)) return false;
   509     if (!Universe::heap()->is_in_permanent(obj)) return false;
   510   }
   511   if (obj != Universe::klassKlassObj()) {
   512     // During a dump, the _klassKlassObj moved to a shared space.
   513     if (DumpSharedSpaces && Universe::klassKlassObj()->is_shared()) {
   514       return true;
   515     }
   516     return false;
   517   }
   519   // Header verification: the mark is typically non-NULL. If we're
   520   // at a safepoint, it must not be null.
   521   // Outside of a safepoint, the header could be changing (for example,
   522   // another thread could be inflating a lock on this object).
   523   if (ignore_mark_word) {
   524     return true;
   525   }
   526   if (mark() != NULL) {
   527     return true;
   528   }
   529   return !SafepointSynchronize::is_at_safepoint();
   530 }
   533 // used only for asserts
   534 inline bool oopDesc::is_oop_or_null(bool ignore_mark_word) const {
   535   return this == NULL ? true : is_oop(ignore_mark_word);
   536 }
   538 #ifndef PRODUCT
   539 // used only for asserts
   540 inline bool oopDesc::is_unlocked_oop() const {
   541   if (!Universe::heap()->is_in_reserved(this)) return false;
   542   return mark()->is_unlocked();
   543 }
   544 #endif // PRODUCT
   546 inline void oopDesc::follow_header() {
   547   if (UseCompressedOops) {
   548     MarkSweep::mark_and_push(compressed_klass_addr());
   549   } else {
   550     MarkSweep::mark_and_push(klass_addr());
   551   }
   552 }
   554 inline void oopDesc::follow_contents(void) {
   555   assert (is_gc_marked(), "should be marked");
   556   blueprint()->oop_follow_contents(this);
   557 }
   560 // Used by scavengers
   562 inline bool oopDesc::is_forwarded() const {
   563   // The extra heap check is needed since the obj might be locked, in which case the
   564   // mark would point to a stack location and have the sentinel bit cleared
   565   return mark()->is_marked();
   566 }
   568 // Used by scavengers
   569 inline void oopDesc::forward_to(oop p) {
   570   assert(Universe::heap()->is_in_reserved(p),
   571          "forwarding to something not in heap");
   572   markOop m = markOopDesc::encode_pointer_as_mark(p);
   573   assert(m->decode_pointer() == p, "encoding must be reversable");
   574   set_mark(m);
   575 }
   577 // Used by parallel scavengers
   578 inline bool oopDesc::cas_forward_to(oop p, markOop compare) {
   579   assert(Universe::heap()->is_in_reserved(p),
   580          "forwarding to something not in heap");
   581   markOop m = markOopDesc::encode_pointer_as_mark(p);
   582   assert(m->decode_pointer() == p, "encoding must be reversable");
   583   return cas_set_mark(m, compare) == compare;
   584 }
   586 // Note that the forwardee is not the same thing as the displaced_mark.
   587 // The forwardee is used when copying during scavenge and mark-sweep.
   588 // It does need to clear the low two locking- and GC-related bits.
   589 inline oop oopDesc::forwardee() const {
   590   return (oop) mark()->decode_pointer();
   591 }
   593 inline bool oopDesc::has_displaced_mark() const {
   594   return mark()->has_displaced_mark_helper();
   595 }
   597 inline markOop oopDesc::displaced_mark() const {
   598   return mark()->displaced_mark_helper();
   599 }
   601 inline void oopDesc::set_displaced_mark(markOop m) {
   602   mark()->set_displaced_mark_helper(m);
   603 }
   605 // The following method needs to be MT safe.
   606 inline int oopDesc::age() const {
   607   assert(!is_forwarded(), "Attempt to read age from forwarded mark");
   608   if (has_displaced_mark()) {
   609     return displaced_mark()->age();
   610   } else {
   611     return mark()->age();
   612   }
   613 }
   615 inline void oopDesc::incr_age() {
   616   assert(!is_forwarded(), "Attempt to increment age of forwarded mark");
   617   if (has_displaced_mark()) {
   618     set_displaced_mark(displaced_mark()->incr_age());
   619   } else {
   620     set_mark(mark()->incr_age());
   621   }
   622 }
   625 inline intptr_t oopDesc::identity_hash() {
   626   // Fast case; if the object is unlocked and the hash value is set, no locking is needed
   627   // Note: The mark must be read into local variable to avoid concurrent updates.
   628   markOop mrk = mark();
   629   if (mrk->is_unlocked() && !mrk->has_no_hash()) {
   630     return mrk->hash();
   631   } else if (mrk->is_marked()) {
   632     return mrk->hash();
   633   } else {
   634     return slow_identity_hash();
   635   }
   636 }
   638 inline void oopDesc::oop_iterate_header(OopClosure* blk) {
   639   if (UseCompressedOops) {
   640     blk->do_oop(compressed_klass_addr());
   641   } else {
   642     blk->do_oop(klass_addr());
   643   }
   644 }
   646 inline void oopDesc::oop_iterate_header(OopClosure* blk, MemRegion mr) {
   647   if (UseCompressedOops) {
   648     if (mr.contains(compressed_klass_addr())) {
   649       blk->do_oop(compressed_klass_addr());
   650     }
   651   } else {
   652     if (mr.contains(klass_addr())) blk->do_oop(klass_addr());
   653   }
   654 }
   656 inline int oopDesc::adjust_pointers() {
   657   debug_only(int check_size = size());
   658   int s = blueprint()->oop_adjust_pointers(this);
   659   assert(s == check_size, "should be the same");
   660   return s;
   661 }
   663 inline void oopDesc::adjust_header() {
   664   if (UseCompressedOops) {
   665     MarkSweep::adjust_pointer(compressed_klass_addr());
   666   } else {
   667     MarkSweep::adjust_pointer(klass_addr());
   668   }
   669 }
   671 #define OOP_ITERATE_DEFN(OopClosureType, nv_suffix)                        \
   672                                                                            \
   673 inline int oopDesc::oop_iterate(OopClosureType* blk) {                     \
   674   SpecializationStats::record_call();                                      \
   675   return blueprint()->oop_oop_iterate##nv_suffix(this, blk);               \
   676 }                                                                          \
   677                                                                            \
   678 inline int oopDesc::oop_iterate(OopClosureType* blk, MemRegion mr) {       \
   679   SpecializationStats::record_call();                                      \
   680   return blueprint()->oop_oop_iterate##nv_suffix##_m(this, blk, mr);       \
   681 }
   683 ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_DEFN)
   684 ALL_OOP_OOP_ITERATE_CLOSURES_3(OOP_ITERATE_DEFN)
   687 inline bool oopDesc::is_shared() const {
   688   return CompactingPermGenGen::is_shared(this);
   689 }
   691 inline bool oopDesc::is_shared_readonly() const {
   692   return CompactingPermGenGen::is_shared_readonly(this);
   693 }
   695 inline bool oopDesc::is_shared_readwrite() const {
   696   return CompactingPermGenGen::is_shared_readwrite(this);
   697 }

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