Mercurial > hg > truffle
view src/share/vm/memory/barrierSet.inline.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 | f95d63e2154a |
children | 3205e78d8193 |
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/* * Copyright (c) 2001, 2010, 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_BARRIERSET_INLINE_HPP #define SHARE_VM_MEMORY_BARRIERSET_INLINE_HPP #include "memory/barrierSet.hpp" #include "memory/cardTableModRefBS.hpp" // Inline functions of BarrierSet, which de-virtualize certain // performance-critical calls when the barrier is the most common // card-table kind. template <class T> void BarrierSet::write_ref_field_pre(T* field, oop new_val) { if (kind() == CardTableModRef) { ((CardTableModRefBS*)this)->inline_write_ref_field_pre(field, new_val); } else { write_ref_field_pre_work(field, new_val); } } void BarrierSet::write_ref_field(void* field, oop new_val) { if (kind() == CardTableModRef) { ((CardTableModRefBS*)this)->inline_write_ref_field(field, new_val); } else { write_ref_field_work(field, new_val); } } // count is number of array elements being written void BarrierSet::write_ref_array(HeapWord* start, size_t count) { assert(count <= (size_t)max_intx, "count too large"); HeapWord* end = (HeapWord*)((char*)start + (count*heapOopSize)); // In the case of compressed oops, start and end may potentially be misaligned; // so we need to conservatively align the first downward (this is not // strictly necessary for current uses, but a case of good hygiene and, // if you will, aesthetics) and the second upward (this is essential for // current uses) to a HeapWord boundary, so we mark all cards overlapping // this write. If this evolves in the future to calling a // logging barrier of narrow oop granularity, like the pre-barrier for G1 // (mentioned here merely by way of example), we will need to change this // interface, so it is "exactly precise" (if i may be allowed the adverbial // redundancy for emphasis) and does not include narrow oop slots not // included in the original write interval. HeapWord* aligned_start = (HeapWord*)align_size_down((uintptr_t)start, HeapWordSize); HeapWord* aligned_end = (HeapWord*)align_size_up ((uintptr_t)end, HeapWordSize); // If compressed oops were not being used, these should already be aligned assert(UseCompressedOops || (aligned_start == start && aligned_end == end), "Expected heap word alignment of start and end"); #if 0 warning("Post:\t" INTPTR_FORMAT "[" SIZE_FORMAT "] : [" INTPTR_FORMAT","INTPTR_FORMAT")\t", start, count, aligned_start, aligned_end); #endif write_ref_array_work(MemRegion(aligned_start, aligned_end)); } void BarrierSet::write_region(MemRegion mr) { if (kind() == CardTableModRef) { ((CardTableModRefBS*)this)->inline_write_region(mr); } else { write_region_work(mr); } } #endif // SHARE_VM_MEMORY_BARRIERSET_INLINE_HPP