1 /*
   2  * Copyright (c) 2012, 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 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.PrimitiveConstant;
  36 import jdk.vm.ci.meta.ResolvedJavaType;
  37 
  38 /**
  39  * This stamp represents the type of the {@link JavaKind#Illegal} value in the second slot of
  40  * {@link JavaKind#Long} and {@link JavaKind#Double} values. It can only appear in framestates or
  41  * virtual objects.
  42  */
  43 public final class IllegalStamp extends Stamp {
  44 
  45     private IllegalStamp() {
  46     }
  47 
  48     @Override
  49     public JavaKind getStackKind() {
  50         return JavaKind.Illegal;
  51     }
  52 
  53     @Override
  54     public LIRKind getLIRKind(LIRKindTool tool) {
  55         return LIRKind.Illegal;
  56     }
  57 
  58     @Override
  59     public Stamp unrestricted() {
  60         return this;
  61     }
  62 
  63     @Override
  64     public boolean isUnrestricted() {
  65         return true;
  66     }
  67 
  68     @Override
  69     public Stamp empty() {
  70         return this;
  71     }
  72 
  73     @Override
  74     public Stamp constant(Constant c, MetaAccessProvider meta) {
  75         assert ((PrimitiveConstant) c).getJavaKind() == JavaKind.Illegal;
  76         return this;
  77     }
  78 
  79     @Override
  80     public ResolvedJavaType javaType(MetaAccessProvider metaAccess) {
  81         throw GraalError.shouldNotReachHere("illegal stamp has no Java type");
  82     }
  83 
  84     @Override
  85     public Stamp meet(Stamp other) {
  86         assert other instanceof IllegalStamp;
  87         return this;
  88     }
  89 
  90     @Override
  91     public Stamp join(Stamp other) {
  92         assert other instanceof IllegalStamp;
  93         return this;
  94     }
  95 
  96     @Override
  97     public boolean isCompatible(Stamp stamp) {
  98         return stamp instanceof IllegalStamp;
  99     }
 100 
 101     @Override
 102     public boolean isCompatible(Constant constant) {
 103         if (constant instanceof PrimitiveConstant) {
 104             PrimitiveConstant prim = (PrimitiveConstant) constant;
 105             return prim.getJavaKind() == JavaKind.Illegal;
 106         }
 107         return false;
 108     }
 109 
 110     @Override
 111     public String toString() {
 112         return "ILLEGAL";
 113     }
 114 
 115     @Override
 116     public boolean hasValues() {
 117         return true;
 118     }
 119 
 120     @Override
 121     public Stamp improveWith(Stamp other) {
 122         assert other instanceof IllegalStamp;
 123         return this;
 124     }
 125 
 126     @Override
 127     public Constant readConstant(MemoryAccessProvider provider, Constant base, long displacement) {
 128         throw GraalError.shouldNotReachHere("can't read values of illegal stamp");
 129     }
 130 
 131     private static final IllegalStamp instance = new IllegalStamp();
 132 
 133     static IllegalStamp getInstance() {
 134         return instance;
 135     }
 136 }