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src/share/vm/runtime/unhandledOops.hpp@9f4457a14b58 (annotated)

src/share/vm/runtime/unhandledOops.hpp

Wed, 09 Apr 2008 15:10:22 -0700

author

rasbold

date

Wed, 09 Apr 2008 15:10:22 -0700

changeset 544

9f4457a14b58

parent 435

a61af66fc99e

child 1907

c18cbe5936b8

permissions

-rw-r--r--

Merge

duke@435	1	/*
duke@435	2	* Copyright 2005 Sun Microsystems, Inc. All Rights Reserved.
duke@435	3	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435	4	*
duke@435	5	* This code is free software; you can redistribute it and/or modify it
duke@435	6	* under the terms of the GNU General Public License version 2 only, as
duke@435	7	* published by the Free Software Foundation.
duke@435	8	*
duke@435	9	* This code is distributed in the hope that it will be useful, but WITHOUT
duke@435	10	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435	11	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
duke@435	12	* version 2 for more details (a copy is included in the LICENSE file that
duke@435	13	* accompanied this code).
duke@435	14	*
duke@435	15	* You should have received a copy of the GNU General Public License version
duke@435	16	* 2 along with this work; if not, write to the Free Software Foundation,
duke@435	17	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435	18	*
duke@435	19	* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
duke@435	20	* CA 95054 USA or visit www.sun.com if you need additional information or
duke@435	21	* have any questions.
duke@435	22	*
duke@435	23	*/
duke@435	24	#ifdef CHECK_UNHANDLED_OOPS
duke@435	25
duke@435	26	// Detect unhanded oops in VM code
duke@435	27
duke@435	28	// The design is that when an oop is declared on the stack as a local
duke@435	29	// variable, the oop is actually a C++ struct with constructor and
duke@435	30	// destructor. The constructor adds the oop address on a list
duke@435	31	// off each thread and the destructor removes the oop. At a potential
duke@435	32	// safepoint, the stack addresses of the local variable oops are trashed
duke@435	33	// with a recognizeable value. If the local variable is used again, it
duke@435	34	// will segfault, indicating an unsafe use of that oop.
duke@435	35	// eg:
duke@435	36	// oop o; //register &o on list
duke@435	37	// funct(); // if potential safepoint - causes clear_naked_oops()
duke@435	38	// // which trashes o above.
duke@435	39	// o->do_something(); // Crashes because o is unsafe.
duke@435	40	//
duke@435	41	// This code implements the details of the unhandled oop list on the thread.
duke@435	42	//
duke@435	43
duke@435	44	class oop;
duke@435	45	class Thread;
duke@435	46
duke@435	47	class UnhandledOopEntry {
duke@435	48	friend class UnhandledOops;
duke@435	49	private:
duke@435	50	oop* _oop_ptr;
duke@435	51	bool _ok_for_gc;
duke@435	52	address _pc;
duke@435	53	public:
duke@435	54	oop* oop_ptr() { return _oop_ptr; }
duke@435	55	UnhandledOopEntry() : _oop_ptr(NULL), _ok_for_gc(false), _pc(NULL) {}
duke@435	56	UnhandledOopEntry(oop* op, address pc) :
duke@435	57	_oop_ptr(op), _ok_for_gc(false), _pc(pc) {}
duke@435	58	};
duke@435	59
duke@435	60
duke@435	61	class UnhandledOops {
duke@435	62	friend class Thread;
duke@435	63	private:
duke@435	64	Thread* _thread;
duke@435	65	int _level;
duke@435	66	GrowableArray<UnhandledOopEntry> *_oop_list;
duke@435	67	void allow_unhandled_oop(oop* op);
duke@435	68	void clear_unhandled_oops();
duke@435	69	UnhandledOops(Thread* thread);
duke@435	70	~UnhandledOops();
duke@435	71
duke@435	72	public:
duke@435	73	static void dump_oops(UnhandledOops* list);
duke@435	74	void register_unhandled_oop(oop* op, address pc);
duke@435	75	void unregister_unhandled_oop(oop* op);
duke@435	76	};
duke@435	77
duke@435	78	#ifdef _LP64
duke@435	79	const intptr_t BAD_OOP_ADDR = 0xfffffffffffffff1;
duke@435	80	#else
duke@435	81	const intptr_t BAD_OOP_ADDR = 0xfffffff1;
duke@435	82	#endif // _LP64
duke@435	83	#endif // CHECK_UNHANDLED_OOPS