Mercurial > hg > truffle
view graal/com.oracle.max.asm/src/com/oracle/max/asm/Label.java @ 4232:382523fc390c
jsr return addresses are valid in registers
author | Christian Wimmer <Christian.Wimmer@Oracle.com> |
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date | Thu, 05 Jan 2012 17:02:13 -0800 |
parents | bc8527f3071c |
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.max.asm; import java.util.ArrayList; /** * This class represents a label within assembly code. */ public final class Label { private int position = -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(AbstractAssembler)} method. */ private ArrayList<Integer> patchPositions = new ArrayList<>(4); /** * 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() { } /** * 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"; patchPositions.add(branchLocation); } protected void patchInstructions(AbstractAssembler masm) { assert isBound() : "Label should be bound"; int target = position; for (int i = 0; i < patchPositions.size(); ++i) { int pos = patchPositions.get(i); masm.patchJumpTarget(pos, target); } } @Override public String toString() { return isBound() ? String.valueOf(position()) : "?"; } }