Mercurial > hg > truffle
view src/share/vm/memory/modRefBarrierSet.hpp @ 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 | 63a4eb8bcd23 3205e78d8193 |
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/* * Copyright (c) 2000, 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. * */ #ifndef SHARE_VM_MEMORY_MODREFBARRIERSET_HPP #define SHARE_VM_MEMORY_MODREFBARRIERSET_HPP #include "memory/barrierSet.hpp" // This kind of "BarrierSet" allows a "CollectedHeap" to detect and // enumerate ref fields that have been modified (since the last // enumeration), using a card table. class OopClosure; class Generation; class ModRefBarrierSet: public BarrierSet { public: ModRefBarrierSet() { _kind = BarrierSet::ModRef; } bool is_a(BarrierSet::Name bsn) { return bsn == BarrierSet::ModRef; } // Barriers only on ref writes. bool has_read_ref_barrier() { return false; } bool has_read_prim_barrier() { return false; } bool has_write_ref_barrier() { return true; } bool has_write_prim_barrier() { return false; } bool read_ref_needs_barrier(void* field) { return false; } bool read_prim_needs_barrier(HeapWord* field, size_t bytes) { return false; } bool write_prim_needs_barrier(HeapWord* field, size_t bytes, juint val1, juint val2) { return false; } void write_prim_field(oop obj, size_t offset, size_t bytes, juint val1, juint val2) {} void read_ref_field(void* field) {} void read_prim_field(HeapWord* field, size_t bytes) {} protected: virtual void write_ref_field_work(void* field, oop new_val) = 0; public: void write_prim_field(HeapWord* field, size_t bytes, juint val1, juint val2) {} bool has_read_ref_array_opt() { return false; } bool has_read_prim_array_opt() { return false; } bool has_write_prim_array_opt() { return false; } bool has_read_region_opt() { return false; } // These operations should assert false unless the correponding operation // above returns true. void read_ref_array(MemRegion mr) { assert(false, "can't call"); } void read_prim_array(MemRegion mr) { assert(false, "can't call"); } void write_prim_array(MemRegion mr) { assert(false, "can't call"); } void read_region(MemRegion mr) { assert(false, "can't call"); } // Causes all refs in "mr" to be assumed to be modified. If "whole_heap" // is true, the caller asserts that the entire heap is being invalidated, // which may admit an optimized implementation for some barriers. virtual void invalidate(MemRegion mr, bool whole_heap = false) = 0; // The caller guarantees that "mr" contains no references. (Perhaps it's // objects have been moved elsewhere.) virtual void clear(MemRegion mr) = 0; // Pass along the argument to the superclass. ModRefBarrierSet(int max_covered_regions) : BarrierSet(max_covered_regions) {} }; #endif // SHARE_VM_MEMORY_MODREFBARRIERSET_HPP