| /* |
| * Copyright (c) 2011, 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.lir; |
| |
| import org.graalvm.compiler.asm.Label; |
| import org.graalvm.compiler.core.common.cfg.AbstractBlockBase; |
| import org.graalvm.compiler.lir.StandardOp.BranchOp; |
| import org.graalvm.compiler.lir.StandardOp.JumpOp; |
| |
| /** |
| * LIR instructions such as {@link JumpOp} and {@link BranchOp} need to reference their target |
| * {@link AbstractBlockBase}. However, direct references are not possible since the control flow |
| * graph (and therefore successors lists) can be changed by optimizations - and fixing the |
| * instructions is error prone. Therefore, we represent an edge to block B from block A via the |
| * tuple {@code (A, |
| * successor-index-of-B)}. That is, indirectly by storing the index into the successor list of A. |
| * Note therefore that the successor list cannot be re-ordered. |
| */ |
| public final class LabelRef { |
| |
| private final LIR lir; |
| private final AbstractBlockBase<?> block; |
| private final int suxIndex; |
| |
| /** |
| * Returns a new reference to a successor of the given block. |
| * |
| * @param block The base block that contains the successor list. |
| * @param suxIndex The index of the successor. |
| * @return The newly created label reference. |
| */ |
| public static LabelRef forSuccessor(final LIR lir, final AbstractBlockBase<?> block, final int suxIndex) { |
| return new LabelRef(lir, block, suxIndex); |
| } |
| |
| /** |
| * Returns a new reference to a successor of the given block. |
| * |
| * @param block The base block that contains the successor list. |
| * @param suxIndex The index of the successor. |
| */ |
| private LabelRef(final LIR lir, final AbstractBlockBase<?> block, final int suxIndex) { |
| this.lir = lir; |
| this.block = block; |
| this.suxIndex = suxIndex; |
| } |
| |
| public AbstractBlockBase<?> getSourceBlock() { |
| return block; |
| } |
| |
| public AbstractBlockBase<?> getTargetBlock() { |
| return block.getSuccessors()[suxIndex]; |
| } |
| |
| public Label label() { |
| return ((StandardOp.LabelOp) lir.getLIRforBlock(getTargetBlock()).get(0)).getLabel(); |
| } |
| |
| @Override |
| public String toString() { |
| return getSourceBlock() + " -> " + (suxIndex < block.getSuccessors().length ? getTargetBlock() : "?"); |
| } |
| } |