1 /* 2 * Copyright (c) 2010, 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 jdk.vm.ci.meta.AllocatableValue; 26 import jdk.vm.ci.meta.ValueKind; 27 28 /** 29 * Represents a compiler spill slot or an outgoing stack-based argument in a method's frame or an 30 * incoming stack-based argument in a method's {@linkplain #isInCallerFrame() caller's frame}. 31 */ 32 public final class StackSlot extends AllocatableValue { 33 34 private final int offset; 35 private final boolean addFrameSize; 36 37 /** 38 * Gets a {@link StackSlot} instance representing a stack slot at a given index holding a value 39 * of a given kind. 40 * 41 * @param kind The kind of the value stored in the stack slot. 42 * @param offset The offset of the stack slot (in bytes) 43 * @param addFrameSize Specifies if the offset is relative to the stack pointer, or the 44 * beginning of the frame (stack pointer + total frame size). 45 */ get(ValueKind<?> kind, int offset, boolean addFrameSize)46 public static StackSlot get(ValueKind<?> kind, int offset, boolean addFrameSize) { 47 assert addFrameSize || offset >= 0; 48 return new StackSlot(kind, offset, addFrameSize); 49 } 50 51 /** 52 * Private constructor to enforce use of {@link #get(ValueKind, int, boolean)} so that a cache 53 * can be used. 54 */ StackSlot(ValueKind<?> kind, int offset, boolean addFrameSize)55 private StackSlot(ValueKind<?> kind, int offset, boolean addFrameSize) { 56 super(kind); 57 this.offset = offset; 58 this.addFrameSize = addFrameSize; 59 } 60 61 /** 62 * Gets the offset of this stack slot, relative to the stack pointer. 63 * 64 * @return The offset of this slot (in bytes). 65 */ getOffset(int totalFrameSize)66 public int getOffset(int totalFrameSize) { 67 assert totalFrameSize > 0 || !addFrameSize; 68 int result = offset + (addFrameSize ? totalFrameSize : 0); 69 assert result >= 0; 70 return result; 71 } 72 isInCallerFrame()73 public boolean isInCallerFrame() { 74 return addFrameSize && offset >= 0; 75 } 76 getRawOffset()77 public int getRawOffset() { 78 return offset; 79 } 80 getRawAddFrameSize()81 public boolean getRawAddFrameSize() { 82 return addFrameSize; 83 } 84 85 @Override toString()86 public String toString() { 87 if (!addFrameSize) { 88 return "out:" + offset + getKindSuffix(); 89 } else if (offset >= 0) { 90 return "in:" + offset + getKindSuffix(); 91 } else { 92 return "stack:" + (-offset) + getKindSuffix(); 93 } 94 } 95 96 /** 97 * Gets this stack slot used to pass an argument from the perspective of a caller. 98 */ asOutArg()99 public StackSlot asOutArg() { 100 assert offset >= 0; 101 if (addFrameSize) { 102 return get(getValueKind(), offset, false); 103 } 104 return this; 105 } 106 107 /** 108 * Gets this stack slot used to pass an argument from the perspective of a callee. 109 */ asInArg()110 public StackSlot asInArg() { 111 assert offset >= 0; 112 if (!addFrameSize) { 113 return get(getValueKind(), offset, true); 114 } 115 return this; 116 } 117 118 @Override hashCode()119 public int hashCode() { 120 final int prime = 37; 121 int result = super.hashCode(); 122 result = prime * result + (addFrameSize ? 1231 : 1237); 123 result = prime * result + offset; 124 return result; 125 } 126 127 @Override equals(Object obj)128 public boolean equals(Object obj) { 129 if (obj instanceof StackSlot) { 130 StackSlot other = (StackSlot) obj; 131 return super.equals(obj) && addFrameSize == other.addFrameSize && offset == other.offset; 132 } 133 return false; 134 } 135 } 136