jdk8-mips64-public/hotspot: src/share/vm/oops/oop.pcgc.inline.hpp@e1162778c1c8

7009266: G1: assert(obj->is_oop_or_null(true )) failed: Error
Summary: A referent object that is only weakly reachable at the start of concurrent marking but is re-attached to the strongly reachable object graph during marking may not be marked as live. This can cause the reference object to be processed prematurely and leave dangling pointers to the referent object. Implement a read barrier for the java.lang.ref.Reference::referent field by intrinsifying the Reference.get() method, and intercepting accesses though JNI, reflection, and Unsafe, so that when a non-null referent object is read it is also logged in an SATB buffer.
Reviewed-by: kvn, iveresov, never, tonyp, dholmes

     1 /*

     2  * Copyright (c) 2005, 2011, 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 #ifndef SHARE_VM_OOPS_OOP_PCGC_INLINE_HPP

    26 #define SHARE_VM_OOPS_OOP_PCGC_INLINE_HPP

    28 #ifndef SERIALGC

    29 #include "gc_implementation/parNew/parNewGeneration.hpp"

    30 #include "gc_implementation/parallelScavenge/parallelScavengeHeap.hpp"

    31 #include "gc_implementation/parallelScavenge/psCompactionManager.hpp"

    32 #include "gc_implementation/parallelScavenge/psParallelCompact.hpp"

    33 #include "gc_implementation/parallelScavenge/psScavenge.hpp"

    34 #include "gc_implementation/parallelScavenge/psScavenge.inline.hpp"

    35 #endif

    37 inline void oopDesc::update_contents(ParCompactionManager* cm) {

    38   // The klass field must be updated before anything else

    39   // can be done.

    40   DEBUG_ONLY(klassOopDesc* original_klass = klass());

    42   // Can the option to update and/or copy be moved up in the

    43   // call chain to avoid calling into here?

    45   if (PSParallelCompact::should_update_klass(klass())) {

    46     update_header();

    47     assert(klass()->is_klass(), "Not updated correctly");

    48   } else {

    49     assert(klass()->is_klass(), "Not updated");

    50   }

    52   Klass* new_klass = blueprint();

    53   if (!new_klass->oop_is_typeArray()) {

    54     // It might contain oops beyond the header, so take the virtual call.

    55     new_klass->oop_update_pointers(cm, this);

    56   }

    57   // Else skip it.  The typeArrayKlass in the header never needs scavenging.

    58 }

    60 inline void oopDesc::follow_contents(ParCompactionManager* cm) {

    61   assert (PSParallelCompact::mark_bitmap()->is_marked(this),

    62     "should be marked");

    63   blueprint()->oop_follow_contents(cm, this);

    64 }

    66 // Used by parallel old GC.

    68 inline void oopDesc::follow_header(ParCompactionManager* cm) {

    69   if (UseCompressedOops) {

    70     PSParallelCompact::mark_and_push(cm, compressed_klass_addr());

    71   } else {

    72     PSParallelCompact::mark_and_push(cm, klass_addr());

    73   }

    74 }

    76 inline oop oopDesc::forward_to_atomic(oop p) {

    77   assert(ParNewGeneration::is_legal_forward_ptr(p),

    78          "illegal forwarding pointer value.");

    79   markOop oldMark = mark();

    80   markOop forwardPtrMark = markOopDesc::encode_pointer_as_mark(p);

    81   markOop curMark;

    83   assert(forwardPtrMark->decode_pointer() == p, "encoding must be reversable");

    84   assert(sizeof(markOop) == sizeof(intptr_t), "CAS below requires this.");

    86   while (!oldMark->is_marked()) {

    87     curMark = (markOop)Atomic::cmpxchg_ptr(forwardPtrMark, &_mark, oldMark);

    88     assert(is_forwarded(), "object should have been forwarded");

    89     if (curMark == oldMark) {

    90       return NULL;

    91     }

    92     // If the CAS was unsuccessful then curMark->is_marked()

    93     // should return true as another thread has CAS'd in another

    94     // forwarding pointer.

    95     oldMark = curMark;

    96   }

    97   return forwardee();

    98 }

   100 inline void oopDesc::update_header() {

   101   if (UseCompressedOops) {

   102     PSParallelCompact::adjust_pointer(compressed_klass_addr());

   103   } else {

   104     PSParallelCompact::adjust_pointer(klass_addr());

   105   }

   106 }

   108 #endif // SHARE_VM_OOPS_OOP_PCGC_INLINE_HPP

Mercurial > jdk8-mips64-public > hotspot / file revision

src/share/vm/oops/oop.pcgc.inline.hpp@e1162778c1c8

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