1 /* 2 * Copyright (c) 2014, 2015, 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 org.graalvm.compiler.core.common.type; 24 25 import org.graalvm.compiler.core.common.LIRKind; 26 import org.graalvm.compiler.core.common.spi.LIRKindTool; 27 import org.graalvm.compiler.debug.GraalError; 28 29 import jdk.vm.ci.meta.Constant; 30 import jdk.vm.ci.meta.JavaKind; 31 import jdk.vm.ci.meta.MemoryAccessProvider; 32 import jdk.vm.ci.meta.MetaAccessProvider; 33 import jdk.vm.ci.meta.ResolvedJavaType; 34 35 /** 36 * Singleton stamp representing the value of type {@code void}. 37 */ 38 public final class VoidStamp extends Stamp { 39 40 private VoidStamp() { 41 } 42 43 @Override 44 public Stamp unrestricted() { 45 return this; 46 } 47 48 @Override 49 public JavaKind getStackKind() { 50 return JavaKind.Void; 51 } 52 53 @Override 54 public Stamp improveWith(Stamp other) { 55 assert other instanceof VoidStamp; 56 return this; 57 } 58 59 @Override 60 public LIRKind getLIRKind(LIRKindTool tool) { 61 throw GraalError.shouldNotReachHere("void stamp has no value"); 62 } 63 64 @Override 65 public ResolvedJavaType javaType(MetaAccessProvider metaAccess) { 66 return metaAccess.lookupJavaType(Void.TYPE); 67 } 68 69 @Override 70 public String toString() { 71 return "void"; 72 } 73 74 @Override 75 public boolean alwaysDistinct(Stamp other) { 76 return this != other; 77 } 78 79 @Override 80 public Stamp meet(Stamp other) { 81 assert other instanceof VoidStamp; 82 return this; 83 } 84 85 @Override 86 public Stamp join(Stamp other) { 87 assert other instanceof VoidStamp; 88 return this; 89 } 90 91 @Override 92 public boolean isCompatible(Stamp stamp) { 93 return stamp instanceof VoidStamp; 94 } 95 96 @Override 97 public boolean isCompatible(Constant constant) { 98 return false; 99 } 100 101 @Override 102 public Stamp empty() { 103 // the void stamp is always empty 104 return this; 105 } 106 107 @Override 108 public boolean hasValues() { 109 return false; 110 } 111 112 @Override 113 public Constant readConstant(MemoryAccessProvider provider, Constant base, long displacement) { 114 throw GraalError.shouldNotReachHere("can't read values of void stamp"); 115 } 116 117 @Override 118 public Stamp constant(Constant c, MetaAccessProvider meta) { 119 throw GraalError.shouldNotReachHere("void stamp has no value"); 120 } 121 122 private static final VoidStamp instance = new VoidStamp(); 123 124 static VoidStamp getInstance() { 125 return instance; 126 } 127 }