jdk8-mips64-public/hotspot: src/share/vm/oops/markOop.inline.hpp@b84fd7d73702

     1 /*

     2  * Copyright (c) 2006, 2012, 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

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    25 #ifndef SHARE_VM_OOPS_MARKOOP_INLINE_HPP

    26 #define SHARE_VM_OOPS_MARKOOP_INLINE_HPP

    28 #include "oops/klass.hpp"

    29 #include "oops/markOop.hpp"

    30 #include "runtime/globals.hpp"

    32 // Should this header be preserved during GC (when biased locking is enabled)?

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

    34   assert(UseBiasedLocking, "unexpected");

    35   if (has_bias_pattern()) {

    36     // Will reset bias at end of collection

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

    38     return false;

    39   }

    40   markOop prototype_header = prototype_for_object(obj_containing_mark);

    41   if (prototype_header->has_bias_pattern()) {

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

    43     // true for correctness

    44     return true;

    45   }

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

    47 }

    49 // Should this header be preserved during GC?

    50 inline bool markOopDesc::must_be_preserved(oop obj_containing_mark) const {

    51   if (!UseBiasedLocking)

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

    53   return must_be_preserved_with_bias(obj_containing_mark);

    54 }

    56 // Should this header be preserved in the case of a promotion failure

    57 // during scavenge (when biased locking is enabled)?

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

    59   assert(UseBiasedLocking, "unexpected");

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

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

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

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

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

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

    66   // the scavengers to call new variants of

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

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

    69   if (has_bias_pattern() ||

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

    71     return true;

    72   }

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

    74 }

    76 // Should this header be preserved in the case of a promotion failure

    77 // during scavenge?

    78 inline bool markOopDesc::must_be_preserved_for_promotion_failure(oop obj_containing_mark) const {

    79   if (!UseBiasedLocking)

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

    81   return must_be_preserved_with_bias_for_promotion_failure(obj_containing_mark);

    82 }

    85 // Same as must_be_preserved_with_bias_for_promotion_failure() except that

    86 // it takes a Klass* argument, instead of the object of which this is the mark word.

    87 inline bool markOopDesc::must_be_preserved_with_bias_for_cms_scavenge(Klass* klass_of_obj_containing_mark) const {

    88   assert(UseBiasedLocking, "unexpected");

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

    90   if (has_bias_pattern() ||

    91       klass_of_obj_containing_mark->prototype_header()->has_bias_pattern()) {

    92     return true;

    93   }

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

    95 }

    97 // Same as must_be_preserved_for_promotion_failure() except that

    98 // it takes a Klass* argument, instead of the object of which this is the mark word.

    99 inline bool markOopDesc::must_be_preserved_for_cms_scavenge(Klass* klass_of_obj_containing_mark) const {

   100   if (!UseBiasedLocking)

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

   102   return must_be_preserved_with_bias_for_cms_scavenge(klass_of_obj_containing_mark);

   103 }

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

   106 #ifdef ASSERT

   107   markOop prototype_header = obj->klass()->prototype_header();

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

   109 #endif

   110   return obj->klass()->prototype_header();

   111 }

   113 #endif // SHARE_VM_OOPS_MARKOOP_INLINE_HPP

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