1 /*
   2  * Copyright (c) 2009, 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.code;
  24 
  25 import static jdk.vm.ci.meta.MetaUtil.identityHashCodeString;
  26 
  27 import jdk.vm.ci.meta.JavaKind;
  28 
  29 /**
  30  * Represents the target machine for a compiler, including the CPU architecture, the size of
  31  * pointers and references, alignment of stacks, caches, etc.
  32  */
  33 public class TargetDescription {
  34 
  35     public final Architecture arch;
  36 
  37     /**
  38      * Specifies if this is a multi-processor system.
  39      */
  40     public final boolean isMP;
  41 
  42     /**
  43      * Specifies if this target supports encoding objects inline in the machine code.
  44      */
  45     public final boolean inlineObjects;
  46 
  47     /**
  48      * The machine word size on this target.
  49      */
  50     public final int wordSize;
  51 
  52     /**
  53      * The {@link JavaKind} to be used for representing raw pointers and CPU registers in Java code.
  54      */
  55     public final JavaKind wordJavaKind;
  56 
  57     /**
  58      * The stack alignment requirement of the platform. For example, from Appendix D of
  59      * <a href="http://www.intel.com/Assets/PDF/manual/248966.pdf">Intel 64 and IA-32 Architectures
  60      * Optimization Reference Manual</a>:
  61      *
  62      * <pre>
  63      *     "It is important to ensure that the stack frame is aligned to a
  64      *      16-byte boundary upon function entry to keep local __m128 data,
  65      *      parameters, and XMM register spill locations aligned throughout
  66      *      a function invocation."
  67      * </pre>
  68      */
  69     public final int stackAlignment;
  70 
  71     /**
  72      * Maximum constant displacement at which a memory access can no longer be an implicit null
  73      * check.
  74      */
  75     public final int implicitNullCheckLimit;
  76 
  77     public TargetDescription(Architecture arch, boolean isMP, int stackAlignment, int implicitNullCheckLimit, boolean inlineObjects) {
  78         this.arch = arch;
  79         this.isMP = isMP;
  80         this.wordSize = arch.getWordSize();
  81         this.wordJavaKind = JavaKind.fromWordSize(wordSize);
  82         this.stackAlignment = stackAlignment;
  83         this.implicitNullCheckLimit = implicitNullCheckLimit;
  84         this.inlineObjects = inlineObjects;
  85 
  86         assert arch.getPlatformKind(wordJavaKind).equals(arch.getWordKind());
  87     }
  88 
  89     @Override
  90     public final int hashCode() {
  91         throw new UnsupportedOperationException();
  92     }
  93 
  94     @Override
  95     public final boolean equals(Object obj) {
  96         if (this == obj) {
  97             return true;
  98         }
  99         if (obj instanceof TargetDescription) {
 100             TargetDescription that = (TargetDescription) obj;
 101             // @formatter:off
 102             if (this.implicitNullCheckLimit == that.implicitNullCheckLimit &&
 103                 this.inlineObjects == that.inlineObjects &&
 104                 this.isMP == that.isMP &&
 105                 this.stackAlignment == that.stackAlignment &&
 106                 this.wordJavaKind.equals(that.wordJavaKind) &&
 107                 this.wordSize == that.wordSize &&
 108                 this.arch.equals(that.arch)) {
 109                 return true;
 110             }
 111             // @formatter:on
 112         }
 113         return false;
 114     }
 115 
 116     @Override
 117     public String toString() {
 118         return identityHashCodeString(this);
 119     }
 120 }