1 /*
 2  * Copyright (c) 2015, 2018, 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 #include "precompiled.hpp"
26 #include "gc/g1/g1OopClosures.inline.hpp"
27 #include "gc/g1/g1RootClosures.hpp"
28 #include "gc/g1/g1SharedClosures.hpp"
29 
30 // Closures used for standard G1 evacuation.
31 class G1EvacuationClosures : public G1EvacuationRootClosures {
32   G1SharedClosures<false> _closures;
33 
34 public:
35   G1EvacuationClosures(G1CollectedHeap* g1h,
36                        G1ParScanThreadState* pss,
37                        bool in_young_gc) :
38       _closures(g1h, pss, in_young_gc) {}
39 
40   OopClosure* weak_oops()   { return &_closures._oops; }
41   OopClosure* strong_oops() { return &_closures._oops; }
42 
43   CLDClosure* weak_clds()             { return &_closures._clds; }
44   CLDClosure* strong_clds()           { return &_closures._clds; }
45 
46   CodeBlobClosure* strong_codeblobs()      { return &_closures._codeblobs; }
47   CodeBlobClosure* weak_codeblobs()        { return &_closures._codeblobs; }
48 };
49 
50 // Closures used during concurrent start.
51 // The treatment of "weak" roots is selectable through the template parameter,
52 // this is usually used to control unloading of classes and interned strings.
53 template <bool should_mark_weak>
54 class G1ConcurrentStartMarkClosures : public G1EvacuationRootClosures {
55   G1SharedClosures<true>             _strong;
56   G1SharedClosures<should_mark_weak> _weak;
57 
58 public:
59   G1ConcurrentStartMarkClosures(G1CollectedHeap* g1h,
60                                 G1ParScanThreadState* pss) :
61       _strong(g1h, pss, /* process_only_dirty_klasses */ false),
62       _weak(g1h, pss,   /* process_only_dirty_klasses */ false) {}
63 
64   OopClosure* weak_oops()   { return &_weak._oops; }
65   OopClosure* strong_oops() { return &_strong._oops; }
66 
67   CLDClosure* weak_clds()             { return &_weak._clds; }
68   CLDClosure* strong_clds()           { return &_strong._clds; }
69 
70   CodeBlobClosure* strong_codeblobs()      { return &_strong._codeblobs; }
71   CodeBlobClosure* weak_codeblobs()        { return &_weak._codeblobs; }
72 };
73 
74 G1EvacuationRootClosures* G1EvacuationRootClosures::create_root_closures(G1ParScanThreadState* pss, G1CollectedHeap* g1h) {
75   G1EvacuationRootClosures* res = NULL;
76   if (g1h->collector_state()->in_concurrent_start_gc()) {
77     if (ClassUnloadingWithConcurrentMark) {
78       res = new G1ConcurrentStartMarkClosures<false>(g1h, pss);
79     } else {
80       res = new G1ConcurrentStartMarkClosures<true>(g1h, pss);
81     }
82   } else {
83     res = new G1EvacuationClosures(g1h, pss, g1h->collector_state()->in_young_only_phase());
84   }
85   return res;
86 }