duke@435: /*
mikael@6198:  * Copyright (c) 2005, 2013, Oracle and/or its affiliates. All rights reserved.
duke@435:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435:  *
duke@435:  * This code is free software; you can redistribute it and/or modify it
duke@435:  * under the terms of the GNU General Public License version 2 only, as
duke@435:  * published by the Free Software Foundation.
duke@435:  *
duke@435:  * This code is distributed in the hope that it will be useful, but WITHOUT
duke@435:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
duke@435:  * version 2 for more details (a copy is included in the LICENSE file that
duke@435:  * accompanied this code).
duke@435:  *
duke@435:  * You should have received a copy of the GNU General Public License version
duke@435:  * 2 along with this work; if not, write to the Free Software Foundation,
duke@435:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435:  *
trims@1907:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@1907:  * or visit www.oracle.com if you need additional information or have any
trims@1907:  * questions.
duke@435:  *
duke@435:  */
stefank@2314: 
stefank@2314: #ifndef SHARE_VM_RUNTIME_UNHANDLEDOOPS_HPP
stefank@2314: #define SHARE_VM_RUNTIME_UNHANDLEDOOPS_HPP
stefank@2314: 
duke@435: #ifdef CHECK_UNHANDLED_OOPS
duke@435: 
duke@435: // Detect unhanded oops in VM code
duke@435: 
duke@435: // The design is that when an oop is declared on the stack as a local
duke@435: // variable, the oop is actually a C++ struct with constructor and
duke@435: // destructor.  The constructor adds the oop address on a list
duke@435: // off each thread and the destructor removes the oop.  At a potential
duke@435: // safepoint, the stack addresses of the local variable oops are trashed
duke@435: // with a recognizeable value.  If the local variable is used again, it
duke@435: // will segfault, indicating an unsafe use of that oop.
duke@435: // eg:
duke@435: //    oop o;    //register &o on list
duke@435: //    funct();  // if potential safepoint - causes clear_naked_oops()
duke@435: //              // which trashes o above.
duke@435: //    o->do_something();  // Crashes because o is unsafe.
duke@435: //
duke@435: // This code implements the details of the unhandled oop list on the thread.
duke@435: //
duke@435: 
duke@435: class oop;
duke@435: class Thread;
duke@435: 
minqi@5103: class UnhandledOopEntry : public CHeapObj<mtThread> {
duke@435:  friend class UnhandledOops;
duke@435:  private:
duke@435:   oop* _oop_ptr;
duke@435:   bool _ok_for_gc;
duke@435:   address _pc;
duke@435:  public:
duke@435:   oop* oop_ptr() { return _oop_ptr; }
duke@435:   UnhandledOopEntry() : _oop_ptr(NULL), _ok_for_gc(false), _pc(NULL) {}
duke@435:   UnhandledOopEntry(oop* op, address pc) :
duke@435:                         _oop_ptr(op),   _ok_for_gc(false), _pc(pc) {}
duke@435: };
duke@435: 
duke@435: 
minqi@5103: class UnhandledOops : public CHeapObj<mtThread> {
duke@435:  friend class Thread;
duke@435:  private:
duke@435:   Thread* _thread;
duke@435:   int _level;
duke@435:   GrowableArray<UnhandledOopEntry> *_oop_list;
duke@435:   void allow_unhandled_oop(oop* op);
duke@435:   void clear_unhandled_oops();
duke@435:   UnhandledOops(Thread* thread);
duke@435:   ~UnhandledOops();
duke@435: 
duke@435:  public:
duke@435:   static void dump_oops(UnhandledOops* list);
duke@435:   void register_unhandled_oop(oop* op, address pc);
duke@435:   void unregister_unhandled_oop(oop* op);
duke@435: };
duke@435: 
duke@435: #ifdef _LP64
duke@435: const intptr_t BAD_OOP_ADDR =  0xfffffffffffffff1;
duke@435: #else
duke@435: const intptr_t BAD_OOP_ADDR =  0xfffffff1;
duke@435: #endif // _LP64
duke@435: #endif // CHECK_UNHANDLED_OOPS
stefank@2314: 
stefank@2314: #endif // SHARE_VM_RUNTIME_UNHANDLEDOOPS_HPP