jdk8-mips64-public/hotspot: src/share/vm/oops/markOop.inline.hpp@75b0f3cb1943

     1 /*

     2  * Copyright 2006 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 // Should this header be preserved during GC?

    26 inline bool markOopDesc::must_be_preserved_with_bias(oop obj_containing_mark) const {

    27   assert(UseBiasedLocking, "unexpected");

    28   if (has_bias_pattern()) {

    29     // Will reset bias at end of collection

    30     // Mark words of biased and currently locked objects are preserved separately

    31     return false;

    32   }

    33   markOop prototype_header = prototype_for_object(obj_containing_mark);

    34   if (prototype_header->has_bias_pattern()) {

    35     // Individual instance which has its bias revoked; must return

    36     // true for correctness

    37     return true;

    38   }

    39   return (!is_unlocked() || !has_no_hash());

    40 }

    42 // Should this header (including its age bits) be preserved in the

    43 // case of a promotion failure during scavenge?

    44 inline bool markOopDesc::must_be_preserved_with_bias_for_promotion_failure(oop obj_containing_mark) const {

    45   assert(UseBiasedLocking, "unexpected");

    46   // We don't explicitly save off the mark words of biased and

    47   // currently-locked objects during scavenges, so if during a

    48   // promotion failure we encounter either a biased mark word or a

    49   // klass which still has a biasable prototype header, we have to

    50   // preserve the mark word. This results in oversaving, but promotion

    51   // failures are rare, and this avoids adding more complex logic to

    52   // the scavengers to call new variants of

    53   // BiasedLocking::preserve_marks() / restore_marks() in the middle

    54   // of a scavenge when a promotion failure has first been detected.

    55   if (has_bias_pattern() ||

    56       prototype_for_object(obj_containing_mark)->has_bias_pattern()) {

    57     return true;

    58   }

    59   return (this != prototype());

    60 }

    62 // Should this header (including its age bits) be preserved in the

    63 // case of a scavenge in which CMS is the old generation?

    64 inline bool markOopDesc::must_be_preserved_with_bias_for_cms_scavenge(klassOop klass_of_obj_containing_mark) const {

    65   assert(UseBiasedLocking, "unexpected");

    66   // CMS scavenges preserve mark words in similar fashion to promotion failures; see above

    67   if (has_bias_pattern() ||

    68       klass_of_obj_containing_mark->klass_part()->prototype_header()->has_bias_pattern()) {

    69     return true;

    70   }

    71   return (this != prototype());

    72 }

    74 inline markOop markOopDesc::prototype_for_object(oop obj) {

    75 #ifdef ASSERT

    76   markOop prototype_header = obj->klass()->klass_part()->prototype_header();

    77   assert(prototype_header == prototype() || prototype_header->has_bias_pattern(), "corrupt prototype header");

    78 #endif

    79   return obj->klass()->klass_part()->prototype_header();

    80 }

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