1/*
2 * Copyright (c) 2005, 2019, 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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23 */
24
25#ifndef SHARE_RUNTIME_UNHANDLEDOOPS_HPP
26#define SHARE_RUNTIME_UNHANDLEDOOPS_HPP
27
28#ifdef CHECK_UNHANDLED_OOPS
29
30// Detect unhanded oops in VM code
31
32// The design is that when an oop is declared on the stack as a local
33// variable, the oop is actually a C++ struct with constructor and
34// destructor. The constructor adds the oop address on a list
35// off each thread and the destructor removes the oop. At a potential
36// safepoint, the stack addresses of the local variable oops are trashed
37// with a recognizable value. If the local variable is used again, it
38// will segfault, indicating an unsafe use of that oop.
39// eg:
40// oop o; //register &o on list
41// funct(); // if potential safepoint - causes clear_naked_oops()
42// // which trashes o above.
43// o->do_something(); // Crashes because o is unsafe.
44//
45// This code implements the details of the unhandled oop list on the thread.
46//
47
48class oop;
49class Thread;
50
51class UnhandledOopEntry : public CHeapObj<mtThread> {
52 friend class UnhandledOops;
53 private:
54 oop* _oop_ptr;
55 bool _ok_for_gc;
56 address _pc;
57 public:
58 oop* oop_ptr() { return _oop_ptr; }
59 UnhandledOopEntry() : _oop_ptr(NULL), _ok_for_gc(false), _pc(NULL) {}
60 UnhandledOopEntry(oop* op, address pc) :
61 _oop_ptr(op), _ok_for_gc(false), _pc(pc) {}
62};
63
64
65class UnhandledOops : public CHeapObj<mtThread> {
66 friend class Thread;
67 private:
68 Thread* _thread;
69 int _level;
70 GrowableArray<UnhandledOopEntry> *_oop_list;
71 void allow_unhandled_oop(oop* op);
72 void clear_unhandled_oops();
73 UnhandledOops(Thread* thread);
74 ~UnhandledOops();
75
76 public:
77 static void dump_oops(UnhandledOops* list);
78 void register_unhandled_oop(oop* op, address pc);
79 void unregister_unhandled_oop(oop* op);
80};
81
82#ifdef _LP64
83const intptr_t BAD_OOP_ADDR = 0xfffffffffffffff1;
84#else
85const intptr_t BAD_OOP_ADDR = 0xfffffff1;
86#endif // _LP64
87#endif // CHECK_UNHANDLED_OOPS
88
89#endif // SHARE_RUNTIME_UNHANDLEDOOPS_HPP
90