| /* |
| * Copyright (c) 2013, 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.graph; |
| |
| /** |
| * An entity that depends upon {@linkplain Graph#maybeCompress() stable} node identifiers. |
| */ |
| class NodeIdAccessor { |
| final Graph graph; |
| final int epoch; |
| |
| NodeIdAccessor(Graph graph) { |
| this.graph = graph; |
| this.epoch = graph.compressions; |
| } |
| |
| Graph getGraph() { |
| return graph; |
| } |
| |
| /** |
| * Verifies that node identifiers have not changed since this object was created. |
| * |
| * @return true if the check succeeds |
| * @throws VerificationError if the check fails |
| */ |
| boolean verifyIdsAreStable() { |
| int compressions = graph.compressions - epoch; |
| if (compressions != 0) { |
| throw new VerificationError("accessing node id in %s across %d graph compression%s", graph, compressions, compressions == 1 ? "" : "s"); |
| } |
| return true; |
| } |
| |
| /** |
| * Gets the identifier for a node. If assertions are enabled, this method asserts that the |
| * identifier is stable. |
| */ |
| int getNodeId(Node node) { |
| assert verifyIdsAreStable(); |
| return node.id(); |
| } |
| } |
