1 /* 2 * Copyright (c) 2013, 2015, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 package org.graalvm.compiler.core.test; 24 25 import org.junit.Assert; 26 import org.junit.Test; 27 28 import org.graalvm.compiler.debug.Debug; 29 import org.graalvm.compiler.debug.Debug.Scope; 30 import org.graalvm.compiler.debug.DebugDumpScope; 31 import org.graalvm.compiler.nodes.ParameterNode; 32 import org.graalvm.compiler.nodes.StructuredGraph; 33 import org.graalvm.compiler.nodes.StructuredGraph.AllowAssumptions; 34 import org.graalvm.compiler.nodes.memory.FloatingReadNode; 35 import org.graalvm.compiler.nodes.spi.LoweringTool; 36 import org.graalvm.compiler.phases.common.CanonicalizerPhase; 37 import org.graalvm.compiler.phases.common.FloatingReadPhase; 38 import org.graalvm.compiler.phases.common.LoweringPhase; 39 import org.graalvm.compiler.phases.common.OptimizeGuardAnchorsPhase; 40 import org.graalvm.compiler.phases.tiers.PhaseContext; 41 42 /* consider 43 * B b = (B) a; 44 * return b.x10; 45 * 46 * With snippets a typecheck is performed and if it was successful, a PiNode is created. 47 * For the read node, however, there is only a dependency to the PiNode, but not to the 48 * typecheck itself. With special crafting, it's possible to get the scheduler moving the 49 * FloatingReadNode before the typecheck. Assuming the object is of the wrong type (here for 50 * example A), an invalid field read is done. 51 * 52 * In order to avoid this situation, an anchor node is introduced in CheckCastSnippts. 53 */ 54 55 public class ReadAfterCheckCastTest extends GraphScheduleTest { 56 57 public static long foo = 0; 58 59 public static class A { 60 61 public long x1; 62 } 63 64 public static class B extends A { 65 66 public long x10; 67 } 68 69 public static long test1Snippet(A a) { 70 if (foo > 4) { 71 B b = (B) a; 72 b.x10 += 1; 73 return b.x10; 74 } else { 75 B b = (B) a; 76 b.x10 += 1; 77 return b.x10; 78 } 79 } 80 81 @Test 82 public void test1() { 83 test("test1Snippet"); 84 } 85 86 @SuppressWarnings("try") 87 private void test(final String snippet) { 88 try (Scope s = Debug.scope("ReadAfterCheckCastTest", new DebugDumpScope(snippet))) { 89 // check shape of graph, with lots of assumptions. will probably fail if graph 90 // structure changes significantly 91 StructuredGraph graph = parseEager(snippet, AllowAssumptions.YES); 92 PhaseContext context = new PhaseContext(getProviders()); 93 CanonicalizerPhase canonicalizer = new CanonicalizerPhase(); 94 new LoweringPhase(canonicalizer, LoweringTool.StandardLoweringStage.HIGH_TIER).apply(graph, context); 95 new FloatingReadPhase().apply(graph); 96 new OptimizeGuardAnchorsPhase().apply(graph); 97 canonicalizer.apply(graph, context); 98 99 Debug.dump(Debug.BASIC_LOG_LEVEL, graph, "After lowering"); 100 101 for (FloatingReadNode node : graph.getNodes(ParameterNode.TYPE).first().usages().filter(FloatingReadNode.class)) { 102 // Checking that the parameter a is not directly used for the access to field 103 // x10 (because x10 must be guarded by the checkcast). 104 Assert.assertTrue(node.getLocationIdentity().isImmutable()); 105 } 106 } catch (Throwable e) { 107 throw Debug.handle(e); 108 } 109 } 110 }