1 /*
   2  * Copyright (c) 2014, 2016, 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 package jdk.vm.ci.hotspot;
  24 
  25 import static jdk.vm.ci.hotspot.HotSpotJVMCIRuntime.runtime;
  26 import static jdk.vm.ci.hotspot.UnsafeAccess.UNSAFE;
  27 
  28 import jdk.vm.ci.meta.Constant;
  29 import sun.misc.Unsafe;
  30 
  31 /**
  32  * Class to access the C++ {@code vmSymbols} table.
  33  */
  34 public final class HotSpotSymbol implements MetaspaceWrapperObject {
  35 
  36     private final String symbol;
  37     private final long pointer;
  38 
  39     HotSpotSymbol(String symbol, long pointer) {
  40         this.symbol = symbol;
  41         this.pointer = pointer;
  42     }
  43 
  44     public String getSymbol() {
  45         return symbol;
  46     }
  47 
  48     public Constant asConstant() {
  49         return HotSpotMetaspaceConstantImpl.forMetaspaceObject(this, false);
  50     }
  51 
  52     @Override
  53     public long getMetaspacePointer() {
  54         return pointer;
  55     }
  56 
  57     @Override
  58     public String toString() {
  59         return "Symbol<" + symbol + ">";
  60     }
  61 
  62     /**
  63      * Returns the symbol in the {@code vmSymbols} table at position {@code index} as {@link String}
  64      * .
  65      *
  66      * @param index position in the symbol table
  67      * @return the symbol at position id
  68      */
  69     static String symbolAt(int index) {
  70         HotSpotJVMCIRuntimeProvider runtime = runtime();
  71         HotSpotVMConfig config = runtime.getConfig();
  72         assert config.vmSymbolsFirstSID <= index && index < config.vmSymbolsSIDLimit : "index " + index + " is out of bounds";
  73         assert config.symbolPointerSize == Unsafe.ADDRESS_SIZE : "the following address read is broken";
  74         return runtime.getCompilerToVM().getSymbol(UNSAFE.getAddress(config.vmSymbolsSymbols + index * config.symbolPointerSize));
  75     }
  76 }