1/*
2 * Copyright (c) 2001, 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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5 * This code is free software; you can redistribute it and/or modify it
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7 * published by the Free Software Foundation.
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10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
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24
25#ifndef SHARE_VM_GC_SERIAL_DEFNEWGENERATION_INLINE_HPP
26#define SHARE_VM_GC_SERIAL_DEFNEWGENERATION_INLINE_HPP
27
28#include "gc/serial/defNewGeneration.hpp"
29#include "gc/shared/cardTableRS.hpp"
30#include "gc/shared/genCollectedHeap.hpp"
31#include "gc/shared/genOopClosures.inline.hpp"
32#include "gc/shared/space.hpp"
33
34// Methods of protected closure types
35
36template <class T>
37inline void DefNewGeneration::KeepAliveClosure::do_oop_work(T* p) {
38#ifdef ASSERT
39  {
40    // We never expect to see a null reference being processed
41    // as a weak reference.
42    assert (!oopDesc::is_null(*p), "expected non-null ref");
43    oop obj = oopDesc::load_decode_heap_oop_not_null(p);
44    assert (obj->is_oop(), "expected an oop while scanning weak refs");
45  }
46#endif // ASSERT
47
48  _cl->do_oop_nv(p);
49
50  // Card marking is trickier for weak refs.
51  // This oop is a 'next' field which was filled in while we
52  // were discovering weak references. While we might not need
53  // to take a special action to keep this reference alive, we
54  // will need to dirty a card as the field was modified.
55  //
56  // Alternatively, we could create a method which iterates through
57  // each generation, allowing them in turn to examine the modified
58  // field.
59  //
60  // We could check that p is also in the old generation, but
61  // dirty cards in the young gen are never scanned, so the
62  // extra check probably isn't worthwhile.
63  if (GenCollectedHeap::heap()->is_in_reserved(p)) {
64    oop obj = oopDesc::load_decode_heap_oop_not_null(p);
65    _rs->inline_write_ref_field_gc(p, obj);
66  }
67}
68
69template <class T>
70inline void DefNewGeneration::FastKeepAliveClosure::do_oop_work(T* p) {
71#ifdef ASSERT
72  {
73    // We never expect to see a null reference being processed
74    // as a weak reference.
75    assert (!oopDesc::is_null(*p), "expected non-null ref");
76    oop obj = oopDesc::load_decode_heap_oop_not_null(p);
77    assert (obj->is_oop(), "expected an oop while scanning weak refs");
78  }
79#endif // ASSERT
80
81  _cl->do_oop_nv(p);
82
83  // Optimized for Defnew generation if it's the youngest generation:
84  // we set a younger_gen card if we have an older->youngest
85  // generation pointer.
86  oop obj = oopDesc::load_decode_heap_oop_not_null(p);
87  if (((HeapWord*)obj < _boundary) && GenCollectedHeap::heap()->is_in_reserved(p)) {
88    _rs->inline_write_ref_field_gc(p, obj);
89  }
90}
91
92#endif // SHARE_VM_GC_SERIAL_DEFNEWGENERATION_INLINE_HPP
93