Mercurial > hg > graal-compiler
diff graal/com.oracle.graal.asm/src/com/oracle/max/asm/Label.java @ 6497:64b7dd2075c0
renamed projects com.oracle.max.asm* to com.oracle.graal.asm*
author | Doug Simon <doug.simon@oracle.com> |
---|---|
date | Wed, 03 Oct 2012 17:42:12 +0200 |
parents | graal/com.oracle.max.asm/src/com/oracle/max/asm/Label.java@bc8527f3071c |
children |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/graal/com.oracle.graal.asm/src/com/oracle/max/asm/Label.java Wed Oct 03 17:42:12 2012 +0200 @@ -0,0 +1,83 @@ +/* + * 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()) : "?"; + } +}