1 /*
   2  * Copyright (c) 2012, 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.PrimitiveConstant;
  34 import jdk.vm.ci.meta.ResolvedJavaType;
  35 
  36 /**
  37  * This stamp represents the type of the {@link JavaKind#Illegal} value in the second slot of
  38  * {@link JavaKind#Long} and {@link JavaKind#Double} values. It can only appear in framestates or
  39  * virtual objects.
  40  */
  41 public final class IllegalStamp extends Stamp {
  42 
  43     private IllegalStamp() {
  44     }
  45 
  46     @Override
  47     public JavaKind getStackKind() {
  48         return JavaKind.Illegal;
  49     }
  50 
  51     @Override
  52     public LIRKind getLIRKind(LIRKindTool tool) {
  53         return LIRKind.Illegal;
  54     }
  55 
  56     @Override
  57     public Stamp unrestricted() {
  58         return this;
  59     }
  60 
  61     @Override
  62     public Stamp empty() {
  63         return this;
  64     }
  65 
  66     @Override
  67     public Stamp constant(Constant c, MetaAccessProvider meta) {
  68         assert ((PrimitiveConstant) c).getJavaKind() == JavaKind.Illegal;
  69         return this;
  70     }
  71 
  72     @Override
  73     public ResolvedJavaType javaType(MetaAccessProvider metaAccess) {
  74         throw GraalError.shouldNotReachHere("illegal stamp has no Java type");
  75     }
  76 
  77     @Override
  78     public Stamp meet(Stamp other) {
  79         assert other instanceof IllegalStamp;
  80         return this;
  81     }
  82 
  83     @Override
  84     public Stamp join(Stamp other) {
  85         assert other instanceof IllegalStamp;
  86         return this;
  87     }
  88 
  89     @Override
  90     public boolean isCompatible(Stamp stamp) {
  91         return stamp instanceof IllegalStamp;
  92     }
  93 
  94     @Override
  95     public boolean isCompatible(Constant constant) {
  96         if (constant instanceof PrimitiveConstant) {
  97             PrimitiveConstant prim = (PrimitiveConstant) constant;
  98             return prim.getJavaKind() == JavaKind.Illegal;
  99         }
 100         return false;
 101     }
 102 
 103     @Override
 104     public String toString() {
 105         return "ILLEGAL";
 106     }
 107 
 108     @Override
 109     public boolean hasValues() {
 110         return true;
 111     }
 112 
 113     @Override
 114     public Stamp improveWith(Stamp other) {
 115         assert other instanceof IllegalStamp;
 116         return this;
 117     }
 118 
 119     @Override
 120     public Constant readConstant(MemoryAccessProvider provider, Constant base, long displacement) {
 121         throw GraalError.shouldNotReachHere("can't read values of illegal stamp");
 122     }
 123 
 124     private static final IllegalStamp instance = new IllegalStamp();
 125 
 126     static IllegalStamp getInstance() {
 127         return instance;
 128     }
 129 }