1 /* 2 * Copyright (c) 2010, 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 jdk.vm.ci.meta.*; 26 27 /** 28 * Represents a compiler spill slot or an outgoing stack-based argument in a method's frame or an 29 * incoming stack-based argument in a method's {@linkplain #isInCallerFrame() caller's frame}. 30 */ 31 public final class StackSlot extends StackSlotValue { 32 33 private final int offset; 34 private final boolean addFrameSize; 35 36 /** 37 * Gets a {@link StackSlot} instance representing a stack slot at a given index holding a value 38 * of a given kind. 39 * 40 * @param kind The kind of the value stored in the stack slot. 41 * @param offset The offset of the stack slot (in bytes) 42 * @param addFrameSize Specifies if the offset is relative to the stack pointer, or the 43 * beginning of the frame (stack pointer + total frame size). 44 */ 45 public static StackSlot get(LIRKind kind, int offset, boolean addFrameSize) { 46 assert addFrameSize || offset >= 0; 47 return new StackSlot(kind, offset, addFrameSize); 48 } 49 50 /** 51 * Private constructor to enforce use of {@link #get(LIRKind, int, boolean)} so that a cache can 52 * be used. 53 */ 54 private StackSlot(LIRKind kind, int offset, boolean addFrameSize) { 55 super(kind); 56 this.offset = offset; 57 this.addFrameSize = addFrameSize; 58 } 59 60 /** 61 * Gets the offset of this stack slot, relative to the stack pointer. 62 * 63 * @return The offset of this slot (in bytes). 64 */ 65 public int getOffset(int totalFrameSize) { 66 assert totalFrameSize > 0 || !addFrameSize; 67 int result = offset + (addFrameSize ? totalFrameSize : 0); 68 assert result >= 0; 69 return result; 70 } 71 72 public boolean isInCallerFrame() { 73 return addFrameSize && offset >= 0; 74 } 75 76 public int getRawOffset() { 77 return offset; 78 } 79 80 public boolean getRawAddFrameSize() { 81 return addFrameSize; 82 } 83 84 @Override 85 public String toString() { 86 if (!addFrameSize) { 87 return "out:" + offset + getKindSuffix(); 88 } else if (offset >= 0) { 89 return "in:" + offset + getKindSuffix(); 90 } else { 91 return "stack:" + (-offset) + getKindSuffix(); 92 } 93 } 94 95 /** 96 * Gets this stack slot used to pass an argument from the perspective of a caller. 97 */ 98 public StackSlot asOutArg() { 99 assert offset >= 0; 100 if (addFrameSize) { 101 return get(getLIRKind(), offset, false); 102 } 103 return this; 104 } 105 106 /** 107 * Gets this stack slot used to pass an argument from the perspective of a callee. 108 */ 109 public StackSlot asInArg() { 110 assert offset >= 0; 111 if (!addFrameSize) { 112 return get(getLIRKind(), offset, true); 113 } 114 return this; 115 } 116 117 @Override 118 public int hashCode() { 119 final int prime = 37; 120 int result = super.hashCode(); 121 result = prime * result + (addFrameSize ? 1231 : 1237); 122 result = prime * result + offset; 123 return result; 124 } 125 126 @Override 127 public boolean equals(Object obj) { 128 if (obj instanceof StackSlot) { 129 StackSlot other = (StackSlot) obj; 130 return super.equals(obj) && addFrameSize == other.addFrameSize && offset == other.offset; 131 } 132 return false; 133 } 134 }