Mercurial > hg > graal-jvmci-8
view graal/com.oracle.jvmci.asm/src/com/oracle/jvmci/asm/Label.java @ 21711:1c41d00e6b2f
moved com.oracle.graal.bytecode to JVMCI namespace (JBS:GRAAL-53)
author | Doug Simon <doug.simon@oracle.com> |
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date | Wed, 03 Jun 2015 21:42:01 +0200 |
parents | 6df25b1418be |
children |
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/* * Copyright (c) 2009, 2011, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package com.oracle.jvmci.asm; import java.util.*; /** * This class represents a label within assembly code. */ public final class Label { private int position = -1; private int blockId = -1; /** * References to instructions that jump to this unresolved label. These instructions need to be * patched when the label is bound using the {@link #patchInstructions(Assembler)} method. */ private ArrayList<Integer> patchPositions = null; /** * Returns the position of this label in the code buffer. * * @return the position */ public int position() { assert position >= 0 : "Unbound label is being referenced"; return position; } public Label() { } public Label(int id) { blockId = id; } public int getBlockId() { return blockId; } /** * Binds the label to the specified position. * * @param pos the position */ protected void bind(int pos) { this.position = pos; assert isBound(); } public boolean isBound() { return position >= 0; } public void addPatchAt(int branchLocation) { assert !isBound() : "Label is already bound " + this + " " + branchLocation + " at position " + position; if (patchPositions == null) { patchPositions = new ArrayList<>(2); } patchPositions.add(branchLocation); } protected void patchInstructions(Assembler masm) { assert isBound() : "Label should be bound"; if (patchPositions != null) { int target = position; for (int i = 0; i < patchPositions.size(); ++i) { int pos = patchPositions.get(i); masm.patchJumpTarget(pos, target); } } } public void reset() { if (this.patchPositions != null) { this.patchPositions.clear(); } this.position = -1; } @Override public String toString() { return isBound() ? String.valueOf(position()) : "?"; } }