Mercurial > hg > truffle
view agent/src/share/classes/sun/jvm/hotspot/memory/SymbolTable.java @ 12837:82af7d7a0128
8003420: NPG: make new GC root for pd_set
Summary: Move protection domain oops from system dictionary entries into a seperate set; the system dictionary references entries in that set now. This allows fast iteration during non-classunloading garbage collection. Implementation based on initial prototype from Ioi Lam (iklam).
Reviewed-by: coleenp, iklam
author | tschatzl |
---|---|
date | Wed, 09 Oct 2013 10:57:01 +0200 |
parents | 1d1603768966 |
children | c90e76575b03 |
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/* * Copyright (c) 2001, 2011, 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. * */ package sun.jvm.hotspot.memory; import java.io.*; import java.util.*; import sun.jvm.hotspot.debugger.*; import sun.jvm.hotspot.oops.*; import sun.jvm.hotspot.types.*; import sun.jvm.hotspot.runtime.*; import sun.jvm.hotspot.utilities.*; public class SymbolTable extends sun.jvm.hotspot.utilities.Hashtable { static { VM.registerVMInitializedObserver(new Observer() { public void update(Observable o, Object data) { initialize(VM.getVM().getTypeDataBase()); } }); } private static synchronized void initialize(TypeDataBase db) { Type type = db.lookupType("SymbolTable"); theTableField = type.getAddressField("_the_table"); symbolTableSize = db.lookupIntConstant("SymbolTable::symbol_table_size").intValue(); } // Fields private static AddressField theTableField; private static int symbolTableSize; // Accessors public static SymbolTable getTheTable() { Address tmp = theTableField.getValue(); return (SymbolTable) VMObjectFactory.newObject(SymbolTable.class, tmp); } public static int getSymbolTableSize() { return symbolTableSize; } public SymbolTable(Address addr) { super(addr); } /** Clone of VM's "temporary" probe routine, as the SA currently does not support mutation so lookup() would have no effect anyway. Returns null if the given string is not in the symbol table. */ public Symbol probe(String name) { try { return probe(toModifiedUTF8Bytes(name)); } catch (IOException e) { return null; } } /** Clone of VM's "temporary" probe routine, as the SA currently does not support mutation so lookup() would have no effect anyway. Returns null if the given string is not in the symbol table. */ public Symbol probe(byte[] name) { long hashValue = hashSymbol(name); for (HashtableEntry e = (HashtableEntry) bucket(hashToIndex(hashValue)); e != null; e = (HashtableEntry) e.next()) { if (e.hash() == hashValue) { Symbol sym = Symbol.create(e.literalValue()); if (sym.equals(name)) { return sym; } } } return null; } public interface SymbolVisitor { public void visit(Symbol sym); } public void symbolsDo(SymbolVisitor visitor) { int numBuckets = tableSize(); for (int i = 0; i < numBuckets; i++) { for (HashtableEntry e = (HashtableEntry) bucket(i); e != null; e = (HashtableEntry) e.next()) { visitor.visit(Symbol.create(e.literalValue())); } } } private static byte[] toModifiedUTF8Bytes(String name) throws IOException { ByteArrayOutputStream baos = new ByteArrayOutputStream(); DataOutputStream dos = new DataOutputStream(baos); dos.writeUTF(name); dos.flush(); byte[] buf = baos.toByteArray(); byte[] res = new byte[buf.length - 2]; // skip the length part System.arraycopy(buf, 2, res, 0, res.length); return res; } }