jdk8-mips64-public/hotspot: src/share/vm/runtime/unhandledOops.hpp@ec173c8f3739

     1 /*

     2  * Copyright (c) 2005, 2010, 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  */

    25 #ifndef SHARE_VM_RUNTIME_UNHANDLEDOOPS_HPP

    26 #define SHARE_VM_RUNTIME_UNHANDLEDOOPS_HPP

    28 #ifdef CHECK_UNHANDLED_OOPS

    30 // Detect unhanded oops in VM code

    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 recognizeable 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 //

    48 class oop;

    49 class Thread;

    51 class 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 };

    65 class 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();

    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 };

    82 #ifdef _LP64

    83 const intptr_t BAD_OOP_ADDR =  0xfffffffffffffff1;

    84 #else

    85 const intptr_t BAD_OOP_ADDR =  0xfffffff1;

    86 #endif // _LP64

    87 #endif // CHECK_UNHANDLED_OOPS

    89 #endif // SHARE_VM_RUNTIME_UNHANDLEDOOPS_HPP

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