| /* |
| * Copyright (c) 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.oops; |
| |
| import java.io.*; |
| import java.util.*; |
| import sun.jvm.hotspot.debugger.*; |
| import sun.jvm.hotspot.runtime.*; |
| import sun.jvm.hotspot.types.*; |
| import sun.jvm.hotspot.utilities.*; |
| |
| // BitData |
| // |
| // A BitData holds a flag or two in its header. |
| public class BitData extends ProfileData { |
| |
| // nullSeen: |
| // saw a null operand (cast/aastore/instanceof) |
| static final int nullSeenFlag = DataLayout.firstFlag + 0; |
| static final int bitCellCount = 0; |
| |
| public BitData(DataLayout layout) { |
| super(layout); |
| } |
| |
| static int staticCellCount() { |
| return bitCellCount; |
| } |
| |
| public int cellCount() { |
| return staticCellCount(); |
| } |
| |
| // Accessor |
| |
| // The nullSeen flag bit is specially known to the interpreter. |
| // Consulting it allows the compiler to avoid setting up nullCheck traps. |
| boolean nullSeen() { return flagAt(nullSeenFlag); } |
| |
| // Code generation support |
| // static int nullSeenByteConstant() { |
| // return flagNumberToByteConstant(nullSeenFlag); |
| // } |
| |
| static int bitDataSize() { |
| return cellOffset(bitCellCount); |
| } |
| |
| public void printDataOn(PrintStream st) { |
| printShared(st, "BitData"); |
| } |
| } |