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comparison src/share/vm/runtime/unhandledOops.hpp @ 0:a61af66fc99e jdk7-b24

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author duke
date Sat, 01 Dec 2007 00:00:00 +0000
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1 /*
2 * Copyright 2005 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
24 #ifdef CHECK_UNHANDLED_OOPS
25
26 // Detect unhanded oops in VM code
27
28 // The design is that when an oop is declared on the stack as a local
29 // variable, the oop is actually a C++ struct with constructor and
30 // destructor. The constructor adds the oop address on a list
31 // off each thread and the destructor removes the oop. At a potential
32 // safepoint, the stack addresses of the local variable oops are trashed
33 // with a recognizeable value. If the local variable is used again, it
34 // will segfault, indicating an unsafe use of that oop.
35 // eg:
36 // oop o; //register &o on list
37 // funct(); // if potential safepoint - causes clear_naked_oops()
38 // // which trashes o above.
39 // o->do_something(); // Crashes because o is unsafe.
40 //
41 // This code implements the details of the unhandled oop list on the thread.
42 //
43
44 class oop;
45 class Thread;
46
47 class UnhandledOopEntry {
48 friend class UnhandledOops;
49 private:
50 oop* _oop_ptr;
51 bool _ok_for_gc;
52 address _pc;
53 public:
54 oop* oop_ptr() { return _oop_ptr; }
55 UnhandledOopEntry() : _oop_ptr(NULL), _ok_for_gc(false), _pc(NULL) {}
56 UnhandledOopEntry(oop* op, address pc) :
57 _oop_ptr(op), _ok_for_gc(false), _pc(pc) {}
58 };
59
60
61 class UnhandledOops {
62 friend class Thread;
63 private:
64 Thread* _thread;
65 int _level;
66 GrowableArray<UnhandledOopEntry> *_oop_list;
67 void allow_unhandled_oop(oop* op);
68 void clear_unhandled_oops();
69 UnhandledOops(Thread* thread);
70 ~UnhandledOops();
71
72 public:
73 static void dump_oops(UnhandledOops* list);
74 void register_unhandled_oop(oop* op, address pc);
75 void unregister_unhandled_oop(oop* op);
76 };
77
78 #ifdef _LP64
79 const intptr_t BAD_OOP_ADDR = 0xfffffffffffffff1;
80 #else
81 const intptr_t BAD_OOP_ADDR = 0xfffffff1;
82 #endif // _LP64
83 #endif // CHECK_UNHANDLED_OOPS