1 /*
 2  * Copyright (c) 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 "code/compiledMethod.hpp"
27 #include "code/nmethod.hpp"
28 #include "gc/shared/gcBehaviours.hpp"
29 
30 IsUnloadingBehaviour* IsUnloadingBehaviour::_current = NULL;
31 
32 class IsCompiledMethodUnloadingOopClosure: public OopClosure {
33   BoolObjectClosure *_cl;
34   bool _is_unloading;
35 
36 public:
37   IsCompiledMethodUnloadingOopClosure(BoolObjectClosure* cl)
38     : _cl(cl),
39       _is_unloading(false)
40   { }
41 
42   virtual void do_oop(oop* p) {
43     if (_is_unloading) {
44       return;
45     }
46     oop obj = *p;
47     if (obj == NULL) {
48       return;
49     }
50     if (!_cl->do_object_b(obj)) {
51       _is_unloading = true;
52     }
53   }
54 
55   virtual void do_oop(narrowOop* p) {
56     ShouldNotReachHere();
57   }
58 
59   bool is_unloading() const {
60     return _is_unloading;
61   }
62 };
63 
64 bool ClosureIsUnloadingBehaviour::is_unloading(CompiledMethod* cm) const {
65   if (cm->is_nmethod()) {
66     IsCompiledMethodUnloadingOopClosure cl(_cl);
67     static_cast<nmethod*>(cm)->oops_do(&cl, true /* allow_dead */);
68     return cl.is_unloading();
69   } else {
70     return false;
71   }
72 }