1 /* 2 * Copyright (c) 2014, 2019, 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 org.graalvm.compiler.core.common.type; 26 27 import org.graalvm.compiler.core.common.LIRKind; 28 import org.graalvm.compiler.core.common.spi.LIRKindTool; 29 import org.graalvm.compiler.debug.GraalError; 30 31 import jdk.vm.ci.meta.Constant; 32 import jdk.vm.ci.meta.JavaKind; 33 import jdk.vm.ci.meta.MemoryAccessProvider; 34 import jdk.vm.ci.meta.MetaAccessProvider; 35 import jdk.vm.ci.meta.ResolvedJavaType; 36 37 /** 38 * Singleton stamp representing the value of type {@code void}. 39 */ 40 public final class VoidStamp extends Stamp { 41 42 private VoidStamp() { 43 } 44 45 @Override 46 public void accept(Visitor v) { 47 } 48 49 @Override 50 public Stamp unrestricted() { 51 return this; 52 } 53 54 @Override 55 public boolean isUnrestricted() { 56 return true; 57 } 58 59 @Override 60 public JavaKind getStackKind() { 61 return JavaKind.Void; 62 } 63 64 @Override 65 public Stamp improveWith(Stamp other) { 66 assert other instanceof VoidStamp; 67 return this; 68 } 69 70 @Override 71 public LIRKind getLIRKind(LIRKindTool tool) { 72 throw GraalError.shouldNotReachHere("void stamp has no value"); 73 } 74 75 @Override 76 public ResolvedJavaType javaType(MetaAccessProvider metaAccess) { 77 return metaAccess.lookupJavaType(Void.TYPE); 78 } 79 80 @Override 81 public String toString() { 82 return "void"; 83 } 84 85 @Override 86 public boolean alwaysDistinct(Stamp other) { 87 return this != other; 88 } 89 90 @Override 91 public Stamp meet(Stamp other) { 92 assert other instanceof VoidStamp; 93 return this; 94 } 95 96 @Override 97 public Stamp join(Stamp other) { 98 assert other instanceof VoidStamp; 99 return this; 100 } 101 102 @Override 103 public boolean isCompatible(Stamp stamp) { 104 return stamp instanceof VoidStamp; 105 } 106 107 @Override 108 public boolean isCompatible(Constant constant) { 109 return false; 110 } 111 112 @Override 113 public Stamp empty() { 114 // the void stamp is always empty 115 return this; 116 } 117 118 @Override 119 public boolean hasValues() { 120 return false; 121 } 122 123 @Override 124 public Constant readConstant(MemoryAccessProvider provider, Constant base, long displacement) { 125 throw GraalError.shouldNotReachHere("can't read values of void stamp"); 126 } 127 128 @Override 129 public Stamp constant(Constant c, MetaAccessProvider meta) { 130 throw GraalError.shouldNotReachHere("void stamp has no value"); 131 } 132 133 private static final VoidStamp instance = new VoidStamp(); 134 135 static VoidStamp getInstance() { 136 return instance; 137 } 138 }