6be8921d13
Reviewed-by: stefank
110 lines
3.6 KiB
C++
110 lines
3.6 KiB
C++
/*
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* Copyright (c) 2015, 2017, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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#ifndef SHARE_GC_Z_ZFORWARDING_INLINE_HPP
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#define SHARE_GC_Z_ZFORWARDING_INLINE_HPP
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#include "gc/z/zForwardingTable.hpp"
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#include "gc/z/zGlobals.hpp"
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#include "gc/z/zHash.inline.hpp"
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#include "runtime/atomic.hpp"
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#include "utilities/debug.hpp"
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inline ZForwardingTable::ZForwardingTable() :
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_table(NULL),
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_size(0) {}
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inline ZForwardingTable::~ZForwardingTable() {
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assert(is_null(), "Should be empty");
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}
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inline ZForwardingTableEntry ZForwardingTable::at(ZForwardingTableCursor* cursor) const {
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return _table[*cursor];
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}
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inline ZForwardingTableEntry ZForwardingTable::first(uintptr_t from_index, ZForwardingTableCursor* cursor) const {
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const size_t mask = _size - 1;
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const size_t hash = ZHash::uint32_to_uint32((uint32_t)from_index);
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*cursor = hash & mask;
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return at(cursor);
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}
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inline ZForwardingTableEntry ZForwardingTable::next(ZForwardingTableCursor* cursor) const {
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const size_t mask = _size - 1;
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*cursor = (*cursor + 1) & mask;
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return at(cursor);
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}
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inline bool ZForwardingTable::is_null() const {
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return _table == NULL;
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}
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inline ZForwardingTableEntry ZForwardingTable::find(uintptr_t from_index) const {
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ZForwardingTableCursor dummy;
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return find(from_index, &dummy);
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}
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inline ZForwardingTableEntry ZForwardingTable::find(uintptr_t from_index, ZForwardingTableCursor* cursor) const {
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// Reading entries in the table races with the atomic CAS done for
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// insertion into the table. This is safe because each entry is at
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// most updated once (from -1 to something else).
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ZForwardingTableEntry entry = first(from_index, cursor);
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while (!entry.is_empty()) {
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if (entry.from_index() == from_index) {
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// Match found, return matching entry
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return entry;
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}
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entry = next(cursor);
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}
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// Match not found, return empty entry
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return entry;
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}
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inline uintptr_t ZForwardingTable::insert(uintptr_t from_index, uintptr_t to_offset, ZForwardingTableCursor* cursor) {
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const ZForwardingTableEntry new_entry(from_index, to_offset);
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const ZForwardingTableEntry old_entry; // empty
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for (;;) {
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const ZForwardingTableEntry prev_entry = Atomic::cmpxchg(new_entry, _table + *cursor, old_entry);
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if (prev_entry.is_empty()) {
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// Success
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return to_offset;
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}
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// Find next empty or matching entry
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ZForwardingTableEntry entry = at(cursor);
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while (!entry.is_empty()) {
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if (entry.from_index() == from_index) {
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// Match found, return already inserted address
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return entry.to_offset();
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}
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entry = next(cursor);
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}
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}
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}
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#endif // SHARE_GC_Z_ZFORWARDING_INLINE_HPP
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