1 /*
   2  * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 package sun.jvm.hotspot.gc.z;
  26 
  27 import sun.jvm.hotspot.debugger.Address;
  28 import sun.jvm.hotspot.debugger.OopHandle;
  29 import sun.jvm.hotspot.runtime.VM;
  30 import sun.jvm.hotspot.types.TypeDataBase;
  31 import sun.jvm.hotspot.types.WrongTypeException;
  32 
  33 class ZAddress {
  34 
  35     private static long ZAddressWeakBadMask;
  36     private static long ZAddressGoodMask;
  37     private static long ZAddressOffsetMask;
  38 
  39     static {
  40         VM.registerVMInitializedObserver((o, d) -> initialize(VM.getVM().getTypeDataBase()));
  41     }
  42 
  43     private static synchronized void initialize(TypeDataBase db) throws WrongTypeException {
  44         ZAddressWeakBadMask = db.lookupLongConstant("ZAddressWeakBadMask").longValue();
  45         ZAddressGoodMask = db.lookupLongConstant("ZAddressGoodMask").longValue();
  46         ZAddressOffsetMask = db.lookupLongConstant("ZAddressOffsetMask").longValue();
  47     }
  48 
  49     static long as_long(Address value) {
  50         if (value == null) {
  51             return 0;
  52         }
  53         return value.asLongValue();
  54     };
  55 
  56     static boolean is_null(Address value) {
  57         return value == null;
  58     }
  59 
  60     static boolean is_weak_bad(Address value) {
  61         return (as_long(value) & ZAddressWeakBadMask) != 0;
  62     }
  63 
  64     static boolean is_weak_good(Address value) {
  65         return !is_weak_bad(value) && !is_null(value);
  66     }
  67 
  68     static boolean is_weak_good_or_null(Address value) {
  69         return !is_weak_bad(value);
  70     }
  71 
  72     static Address offset(Address address) {
  73         return address.andWithMask(ZAddressOffsetMask);
  74     }
  75 
  76     static Address address(Address addr) {
  77         // TODO: Linux-specific - We don't use a heap base on Linux
  78         return ZOop.to_address(addr);
  79     }
  80 
  81     static Address good(Address value) {
  82         return address(offset(value).orWithMask(ZAddressGoodMask));
  83     }
  84 
  85     static Address good_or_null(Address value) {
  86         return is_null(value) ? value : good(value);
  87     }
  88 }