Mercurial > hg > truffle
view src/share/vm/memory/genRemSet.cpp @ 12301:2c022e432e10
8024974: Incorrect use of GC_locker::is_active()
Summary: SymbolTable and StringTable can make calls to GC_locker::is_active() outside a safepoint. This isn't safe because the GC_locker active state (lock count) is only updated at a safepoint and only remains valid as long as _needs_gc is true. However, outside a safepoint_needs_gc can change to false at any time, which makes it impossible to do a correct call to is_active() in that context. In this case these calls can just be removed since the input argument to basic_add() should never be on the heap and so there's no need to check the GC_locker state. This change also adjusts the assert() in is_active() to makes sure all calls to this function are always done under a safepoint.
Reviewed-by: brutisso, dcubed
Contributed-by: per.liden@oracle.com
author | stefank |
---|---|
date | Fri, 20 Sep 2013 10:53:28 +0200 |
parents | da91efe96a93 |
children | ab68fc0101ce |
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/* * Copyright (c) 2001, 2012, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. * */ #include "precompiled.hpp" #include "classfile/classLoaderData.hpp" #include "memory/cardTableRS.hpp" #include "memory/genRemSet.hpp" // This kind of "BarrierSet" allows a "CollectedHeap" to detect and // enumerate ref fields that have been modified (since the last // enumeration.) uintx GenRemSet::max_alignment_constraint(Name nm) { switch (nm) { case GenRemSet::CardTable: return CardTableRS::ct_max_alignment_constraint(); default: guarantee(false, "Unrecognized GenRemSet type."); return (0); // Make Windows compiler happy } } class HasAccumulatedModifiedOopsClosure : public KlassClosure { bool _found; public: HasAccumulatedModifiedOopsClosure() : _found(false) {} void do_klass(Klass* klass) { if (_found) { return; } if (klass->has_accumulated_modified_oops()) { _found = true; } } bool found() { return _found; } }; bool KlassRemSet::mod_union_is_clear() { HasAccumulatedModifiedOopsClosure closure; ClassLoaderDataGraph::classes_do(&closure); return !closure.found(); } class ClearKlassModUnionClosure : public KlassClosure { public: void do_klass(Klass* klass) { if (klass->has_accumulated_modified_oops()) { klass->clear_accumulated_modified_oops(); } } }; void KlassRemSet::clear_mod_union() { ClearKlassModUnionClosure closure; ClassLoaderDataGraph::classes_do(&closure); }