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src/share/vm/oops/oop.pcgc.inline.hpp@e1162778c1c8 (annotated)

src/share/vm/oops/oop.pcgc.inline.hpp

Thu, 07 Apr 2011 09:53:20 -0700

author

johnc

date

Thu, 07 Apr 2011 09:53:20 -0700

changeset 2781

e1162778c1c8

parent 2534

e5383553fd4e

child 4037

da91efe96a93

permissions

-rw-r--r--

7009266: G1: assert(obj->is_oop_or_null(true )) failed: Error
Summary: A referent object that is only weakly reachable at the start of concurrent marking but is re-attached to the strongly reachable object graph during marking may not be marked as live. This can cause the reference object to be processed prematurely and leave dangling pointers to the referent object. Implement a read barrier for the java.lang.ref.Reference::referent field by intrinsifying the Reference.get() method, and intercepting accesses though JNI, reflection, and Unsafe, so that when a non-null referent object is read it is also logged in an SATB buffer.
Reviewed-by: kvn, iveresov, never, tonyp, dholmes

duke@435	1	/*
stefank@2534	2	* Copyright (c) 2005, 2011, Oracle and/or its affiliates. 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	*
trims@1907	19	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@1907	20	* or visit www.oracle.com if you need additional information or have any
trims@1907	21	* questions.
duke@435	22	*
duke@435	23	*/
duke@435	24
stefank@2314	25	#ifndef SHARE_VM_OOPS_OOP_PCGC_INLINE_HPP
stefank@2314	26	#define SHARE_VM_OOPS_OOP_PCGC_INLINE_HPP
stefank@2314	27
stefank@2314	28	#ifndef SERIALGC
stefank@2314	29	#include "gc_implementation/parNew/parNewGeneration.hpp"
stefank@2314	30	#include "gc_implementation/parallelScavenge/parallelScavengeHeap.hpp"
stefank@2314	31	#include "gc_implementation/parallelScavenge/psCompactionManager.hpp"
stefank@2314	32	#include "gc_implementation/parallelScavenge/psParallelCompact.hpp"
stefank@2314	33	#include "gc_implementation/parallelScavenge/psScavenge.hpp"
stefank@2314	34	#include "gc_implementation/parallelScavenge/psScavenge.inline.hpp"
stefank@2314	35	#endif
stefank@2314	36
duke@435	37	inline void oopDesc::update_contents(ParCompactionManager* cm) {
duke@435	38	// The klass field must be updated before anything else
duke@435	39	// can be done.
duke@435	40	DEBUG_ONLY(klassOopDesc* original_klass = klass());
duke@435	41
duke@435	42	// Can the option to update and/or copy be moved up in the
duke@435	43	// call chain to avoid calling into here?
duke@435	44
duke@435	45	if (PSParallelCompact::should_update_klass(klass())) {
duke@435	46	update_header();
duke@435	47	assert(klass()->is_klass(), "Not updated correctly");
duke@435	48	} else {
duke@435	49	assert(klass()->is_klass(), "Not updated");
duke@435	50	}
duke@435	51
duke@435	52	Klass* new_klass = blueprint();
duke@435	53	if (!new_klass->oop_is_typeArray()) {
duke@435	54	// It might contain oops beyond the header, so take the virtual call.
duke@435	55	new_klass->oop_update_pointers(cm, this);
duke@435	56	}
duke@435	57	// Else skip it. The typeArrayKlass in the header never needs scavenging.
duke@435	58	}
duke@435	59
duke@435	60	inline void oopDesc::follow_contents(ParCompactionManager* cm) {
duke@435	61	assert (PSParallelCompact::mark_bitmap()->is_marked(this),
duke@435	62	"should be marked");
duke@435	63	blueprint()->oop_follow_contents(cm, this);
duke@435	64	}
duke@435	65
duke@435	66	// Used by parallel old GC.
duke@435	67
duke@435	68	inline void oopDesc::follow_header(ParCompactionManager* cm) {
coleenp@548	69	if (UseCompressedOops) {
coleenp@548	70	PSParallelCompact::mark_and_push(cm, compressed_klass_addr());
coleenp@548	71	} else {
coleenp@548	72	PSParallelCompact::mark_and_push(cm, klass_addr());
coleenp@548	73	}
duke@435	74	}
duke@435	75
duke@435	76	inline oop oopDesc::forward_to_atomic(oop p) {
duke@435	77	assert(ParNewGeneration::is_legal_forward_ptr(p),
duke@435	78	"illegal forwarding pointer value.");
duke@435	79	markOop oldMark = mark();
duke@435	80	markOop forwardPtrMark = markOopDesc::encode_pointer_as_mark(p);
duke@435	81	markOop curMark;
duke@435	82
duke@435	83	assert(forwardPtrMark->decode_pointer() == p, "encoding must be reversable");
duke@435	84	assert(sizeof(markOop) == sizeof(intptr_t), "CAS below requires this.");
duke@435	85
johnc@2334	86	while (!oldMark->is_marked()) {
duke@435	87	curMark = (markOop)Atomic::cmpxchg_ptr(forwardPtrMark, &_mark, oldMark);
johnc@2334	88	assert(is_forwarded(), "object should have been forwarded");
duke@435	89	if (curMark == oldMark) {
duke@435	90	return NULL;
duke@435	91	}
johnc@2334	92	// If the CAS was unsuccessful then curMark->is_marked()
johnc@2334	93	// should return true as another thread has CAS'd in another
johnc@2334	94	// forwarding pointer.
duke@435	95	oldMark = curMark;
duke@435	96	}
duke@435	97	return forwardee();
duke@435	98	}
duke@435	99
duke@435	100	inline void oopDesc::update_header() {
coleenp@548	101	if (UseCompressedOops) {
coleenp@548	102	PSParallelCompact::adjust_pointer(compressed_klass_addr());
coleenp@548	103	} else {
coleenp@548	104	PSParallelCompact::adjust_pointer(klass_addr());
coleenp@548	105	}
duke@435	106	}
duke@435	107
stefank@2314	108	#endif // SHARE_VM_OOPS_OOP_PCGC_INLINE_HPP