1 /*
   2  * Copyright (c) 2013, 2014, 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 java.util.Arrays;
  26 import java.util.HashMap;
  27 import java.util.HashSet;
  28 import java.util.Map;
  29 import java.util.TreeMap;
  30 
  31 /**
  32  * A map from registers to frame slots. This can be used to describe where callee saved registers
  33  * are saved in a callee's frame.
  34  */
  35 public final class RegisterSaveLayout {
  36 
  37     /**
  38      * Keys.
  39      */
  40     private final Register[] registers;
  41 
  42     /**
  43      * Slot indexes relative to stack pointer.
  44      */
  45     private final int[] slots;
  46 
  47     /**
  48      * Creates a map from registers to frame slots.
  49      *
  50      * @param registers the keys in the map
  51      * @param slots frame slot index for each register in {@code registers}
  52      */
  53     @SuppressFBWarnings(value = "EI_EXPOSE_REP2", justification = "caller transfers ownership of `registers` and `slots`")
  54     public RegisterSaveLayout(Register[] registers, int[] slots) {
  55         assert registers.length == slots.length;
  56         this.registers = registers;
  57         this.slots = slots;
  58         assert registersToSlots(false).size() == registers.length : "non-unique registers";
  59         assert new HashSet<>(registersToSlots(false).values()).size() == slots.length : "non-unqiue slots";
  60     }
  61 
  62     /**
  63      * Gets the frame slot index for a given register.
  64      *
  65      * @param register register to get the frame slot index for
  66      * @return frame slot index
  67      */
  68     public int registerToSlot(Register register) {
  69         for (int i = 0; i < registers.length; i++) {
  70             if (register.equals(registers[i])) {
  71                 return slots[i];
  72             }
  73         }
  74         throw new IllegalArgumentException(register + " not saved by this layout: " + this);
  75     }
  76 
  77     /**
  78      * Gets this layout information as a {@link Map} from registers to slots.
  79      */
  80     public Map<Register, Integer> registersToSlots(boolean sorted) {
  81         Map<Register, Integer> result;
  82         if (sorted) {
  83             result = new TreeMap<>();
  84         } else {
  85             result = new HashMap<>();
  86         }
  87         for (int i = 0; i < registers.length; i++) {
  88             result.put(registers[i], slots[i]);
  89         }
  90         return result;
  91     }
  92 
  93     /**
  94      * Gets this layout information as a {@link Map} from slots to registers.
  95      */
  96     public Map<Integer, Register> slotsToRegisters(boolean sorted) {
  97         Map<Integer, Register> result;
  98         if (sorted) {
  99             result = new TreeMap<>();
 100         } else {
 101             result = new HashMap<>();
 102         }
 103         for (int i = 0; i < registers.length; i++) {
 104             result.put(slots[i], registers[i]);
 105         }
 106         return result;
 107     }
 108 
 109     @Override
 110     public int hashCode() {
 111         throw new UnsupportedOperationException();
 112     }
 113 
 114     @Override
 115     public boolean equals(Object obj) {
 116         if (this == obj) {
 117             return true;
 118         }
 119         if (obj instanceof RegisterSaveLayout) {
 120             RegisterSaveLayout that = (RegisterSaveLayout) obj;
 121             if (Arrays.equals(registers, that.registers) && Arrays.equals(slots, that.slots)) {
 122                 return true;
 123             }
 124         }
 125         return false;
 126     }
 127 
 128     @Override
 129     public String toString() {
 130         return registersToSlots(true).toString();
 131     }
 132 }