aoqi@0: /*
aoqi@0:  * Copyright (c) 2005, 2013, Oracle and/or its affiliates. All rights reserved.
aoqi@0:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
aoqi@0:  *
aoqi@0:  * This code is free software; you can redistribute it and/or modify it
aoqi@0:  * under the terms of the GNU General Public License version 2 only, as
aoqi@0:  * published by the Free Software Foundation.
aoqi@0:  *
aoqi@0:  * This code is distributed in the hope that it will be useful, but WITHOUT
aoqi@0:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
aoqi@0:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
aoqi@0:  * version 2 for more details (a copy is included in the LICENSE file that
aoqi@0:  * accompanied this code).
aoqi@0:  *
aoqi@0:  * You should have received a copy of the GNU General Public License version
aoqi@0:  * 2 along with this work; if not, write to the Free Software Foundation,
aoqi@0:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
aoqi@0:  *
aoqi@0:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
aoqi@0:  * or visit www.oracle.com if you need additional information or have any
aoqi@0:  * questions.
aoqi@0:  *
aoqi@0:  */
aoqi@0: 
aoqi@0: #ifndef SHARE_VM_RUNTIME_UNHANDLEDOOPS_HPP
aoqi@0: #define SHARE_VM_RUNTIME_UNHANDLEDOOPS_HPP
aoqi@0: 
aoqi@0: #ifdef CHECK_UNHANDLED_OOPS
aoqi@0: 
aoqi@0: // Detect unhanded oops in VM code
aoqi@0: 
aoqi@0: // The design is that when an oop is declared on the stack as a local
aoqi@0: // variable, the oop is actually a C++ struct with constructor and
aoqi@0: // destructor.  The constructor adds the oop address on a list
aoqi@0: // off each thread and the destructor removes the oop.  At a potential
aoqi@0: // safepoint, the stack addresses of the local variable oops are trashed
aoqi@0: // with a recognizeable value.  If the local variable is used again, it
aoqi@0: // will segfault, indicating an unsafe use of that oop.
aoqi@0: // eg:
aoqi@0: //    oop o;    //register &o on list
aoqi@0: //    funct();  // if potential safepoint - causes clear_naked_oops()
aoqi@0: //              // which trashes o above.
aoqi@0: //    o->do_something();  // Crashes because o is unsafe.
aoqi@0: //
aoqi@0: // This code implements the details of the unhandled oop list on the thread.
aoqi@0: //
aoqi@0: 
aoqi@0: class oop;
aoqi@0: class Thread;
aoqi@0: 
aoqi@0: class UnhandledOopEntry : public CHeapObj<mtThread> {
aoqi@0:  friend class UnhandledOops;
aoqi@0:  private:
aoqi@0:   oop* _oop_ptr;
aoqi@0:   bool _ok_for_gc;
aoqi@0:   address _pc;
aoqi@0:  public:
aoqi@0:   oop* oop_ptr() { return _oop_ptr; }
aoqi@0:   UnhandledOopEntry() : _oop_ptr(NULL), _ok_for_gc(false), _pc(NULL) {}
aoqi@0:   UnhandledOopEntry(oop* op, address pc) :
aoqi@0:                         _oop_ptr(op),   _ok_for_gc(false), _pc(pc) {}
aoqi@0: };
aoqi@0: 
aoqi@0: 
aoqi@0: class UnhandledOops : public CHeapObj<mtThread> {
aoqi@0:  friend class Thread;
aoqi@0:  private:
aoqi@0:   Thread* _thread;
aoqi@0:   int _level;
aoqi@0:   GrowableArray<UnhandledOopEntry> *_oop_list;
aoqi@0:   void allow_unhandled_oop(oop* op);
aoqi@0:   void clear_unhandled_oops();
aoqi@0:   UnhandledOops(Thread* thread);
aoqi@0:   ~UnhandledOops();
aoqi@0: 
aoqi@0:  public:
aoqi@0:   static void dump_oops(UnhandledOops* list);
aoqi@0:   void register_unhandled_oop(oop* op, address pc);
aoqi@0:   void unregister_unhandled_oop(oop* op);
aoqi@0: };
aoqi@0: 
aoqi@0: #ifdef _LP64
aoqi@0: const intptr_t BAD_OOP_ADDR =  0xfffffffffffffff1;
aoqi@0: #else
aoqi@0: const intptr_t BAD_OOP_ADDR =  0xfffffff1;
aoqi@0: #endif // _LP64
aoqi@0: #endif // CHECK_UNHANDLED_OOPS
aoqi@0: 
aoqi@0: #endif // SHARE_VM_RUNTIME_UNHANDLEDOOPS_HPP