| /* |
| * 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 org.graalvm.compiler.asm; |
| |
| import java.util.ArrayList; |
| |
| /** |
| * 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()) : "?"; |
| } |
| } |