1 /*
   2  * Copyright (c) 2005, 2008, 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  */
  24 
  25 inline void oopDesc::update_contents(ParCompactionManager* cm) {
  26   // The klass field must be updated before anything else
  27   // can be done.
  28   DEBUG_ONLY(klassOopDesc* original_klass = klass());
  29 
  30   // Can the option to update and/or copy be moved up in the
  31   // call chain to avoid calling into here?
  32 
  33   if (PSParallelCompact::should_update_klass(klass())) {
  34     update_header();
  35     assert(klass()->is_klass(), "Not updated correctly");
  36   } else {
  37     assert(klass()->is_klass(), "Not updated");
  38   }
  39 
  40   Klass* new_klass = blueprint();
  41   if (!new_klass->oop_is_typeArray()) {
  42     // It might contain oops beyond the header, so take the virtual call.
  43     new_klass->oop_update_pointers(cm, this);
  44   }
  45   // Else skip it.  The typeArrayKlass in the header never needs scavenging.
  46 }
  47 
  48 inline void oopDesc::update_contents(ParCompactionManager* cm,
  49                                      HeapWord* begin_limit,
  50                                      HeapWord* end_limit) {
  51   // The klass field must be updated before anything else
  52   // can be done.
  53   debug_only(klassOopDesc* original_klass = klass());
  54 
  55   update_contents(cm, klass(), begin_limit, end_limit);
  56 }
  57 
  58 inline void oopDesc::update_contents(ParCompactionManager* cm,
  59                                      klassOop old_klass,
  60                                      HeapWord* begin_limit,
  61                                      HeapWord* end_limit) {
  62 
  63   klassOop updated_klass =
  64     PSParallelCompact::summary_data().calc_new_klass(old_klass);
  65 
  66   // Needs to be boundary aware for the 64 bit case
  67   // update_header();
  68   // The klass has moved.  Is the location of the klass
  69   // within the limits?
  70   if ((((HeapWord*)&_metadata._klass) >= begin_limit) &&
  71       (((HeapWord*)&_metadata._klass) < end_limit)) {
  72     set_klass(updated_klass);
  73   }
  74 
  75   Klass* klass = updated_klass->klass_part();
  76   if (!klass->oop_is_typeArray()) {
  77     // It might contain oops beyond the header, so take the virtual call.
  78     klass->oop_update_pointers(cm, this, begin_limit, end_limit);
  79   }
  80   // Else skip it.  The typeArrayKlass in the header never needs scavenging.
  81 }
  82 
  83 inline void oopDesc::follow_contents(ParCompactionManager* cm) {
  84   assert (PSParallelCompact::mark_bitmap()->is_marked(this),
  85     "should be marked");
  86   blueprint()->oop_follow_contents(cm, this);
  87 }
  88 
  89 // Used by parallel old GC.
  90 
  91 inline void oopDesc::follow_header(ParCompactionManager* cm) {
  92   if (UseCompressedOops) {
  93     PSParallelCompact::mark_and_push(cm, compressed_klass_addr());
  94   } else {
  95     PSParallelCompact::mark_and_push(cm, klass_addr());
  96   }
  97 }
  98 
  99 inline oop oopDesc::forward_to_atomic(oop p) {
 100   assert(ParNewGeneration::is_legal_forward_ptr(p),
 101          "illegal forwarding pointer value.");
 102   markOop oldMark = mark();
 103   markOop forwardPtrMark = markOopDesc::encode_pointer_as_mark(p);
 104   markOop curMark;
 105 
 106   assert(forwardPtrMark->decode_pointer() == p, "encoding must be reversable");
 107   assert(sizeof(markOop) == sizeof(intptr_t), "CAS below requires this.");
 108 
 109   while (!is_forwarded()) {
 110     curMark = (markOop)Atomic::cmpxchg_ptr(forwardPtrMark, &_mark, oldMark);
 111     if (curMark == oldMark) {
 112       assert(is_forwarded(), "the CAS should have succeeded.");
 113       return NULL;
 114     }
 115     oldMark = curMark;
 116   }
 117   return forwardee();
 118 }
 119 
 120 inline void oopDesc::update_header() {
 121   if (UseCompressedOops) {
 122     PSParallelCompact::adjust_pointer(compressed_klass_addr());
 123   } else {
 124     PSParallelCompact::adjust_pointer(klass_addr());
 125   }
 126 }
 127 
 128 inline void oopDesc::update_header(HeapWord* beg_addr, HeapWord* end_addr) {
 129   if (UseCompressedOops) {
 130     PSParallelCompact::adjust_pointer(compressed_klass_addr(),
 131                                       beg_addr, end_addr);
 132   } else {
 133     PSParallelCompact::adjust_pointer(klass_addr(), beg_addr, end_addr);
 134   }
 135 }